JPH109839A - Surface flaw inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically and accurately process a surface flaw at a high speed even if a surface to be inspected is a complicated curved surface. SOLUTION: In a surface flaw inspection apparatus wherein a surface to be inspected is irradiated with light and a light detection image is formed on the basis of the reflected light from the surface to be inspected and the flaw of the surface to be inspected on the basis of the light detection image, an illumination means 1 having a gate-shaped surrounding the body 5 being matter to be inspected and forming a predetermined light and shade pattern on the surface to be inspected, an imaging device fixing means 2 having a gate shape surrounding the matter to be inspected and having a plurality of imaging devices 3 forming a light detection image on the basis of the reflected light from the surface to be inspected attached thereto at predetermined positions and an inspection processing means 4 detecting the flaw on the surface to be inspected on the basis of the light detection image obtained by the above mentioned imaging devices are provided and, at a point of time when the matter to be inspected moves to pass through the illumination means and an imaging device processing and fixing means, the surface to be inspected is inspected.

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 an 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, JP-A-64-38638. This involves forming a band of light on the surface to be inspected, moving the band of light over the surface to be inspected, recording the reflected image continuously and stepwise, and finally recording these partial images. Is edited into an overall image, and a defect on the surface to be inspected and coordinate information of the defect are output.

[0003]

However, the conventional surface defect inspection apparatus as described above has the following problems. For example, in a defect inspection of a painted surface of an automobile body, in a curved surface region of a vehicle body, the reflection direction of the light band (light band) changes according to the curvature, and this reflection image is always displayed on an image center of a video camera. Such control is required. Further, since the curved surface of the vehicle body differs for each part or vehicle type, the above control becomes more complicated.

The defect detection utilizes the fact that the reflected image of the light band appears as a dark portion or a change in the contour of the image in the light band. The method and apparatus for automatically detecting the defect are not disclosed. There was a problem that it was not described.

The present invention has been made to solve the problems of the prior art as described above, and can automatically, accurately and quickly process surface defects even if the surface to be inspected is a complicated curved surface. It is an object to provide a surface defect inspection device.

[0006]

In order to achieve the above object, the present invention irradiates a surface to be inspected with light, creates a light-receiving image based on the reflected light from the surface to be inspected, and generates a light-receiving image based on the light-receiving image. In a surface defect inspection apparatus for detecting a defect on a surface to be inspected based on a lighting device for forming a predetermined light and dark pattern on the surface to be inspected in a gate-shaped shape surrounding the object to be inspected, An imaging device fixing means configured such that a plurality of imaging devices that create a received light image based on reflected light from a surface to be inspected in a portal shape are attached at predetermined positions,
Inspection processing means for detecting a defect on the surface to be inspected based on the received light image obtained from the imaging device and outputting the result, wherein the object to be inspected moves and the illumination means and the imaging device processing fixing means At the time of passing the inspection.

Further, according to the present invention, the portal shape of the illuminating means is configured to be a shape substantially adapted to the cross-sectional contour of the object to be inspected.

In the present invention, the illuminating means is configured such that a plurality of light sources are attached to the portal-shaped white background plate at substantially equal intervals.

Further, in the present invention, the illuminating means is provided with a light-diffusing sheet having a matte black predetermined light-dark pattern formed inside the light source, that is, on the side of the surface to be inspected. The diffused light of the pattern and the surface illumination are used to irradiate the surface to be inspected.

Further, the present invention is configured such that the interval between the light and dark patterns changes based on the number of light and dark patterns reflected on the CCD camera.

Further, in the present invention, the diffuser sheet is stretched by a matte black sheet guide having the same gate shape as the illuminating means, and the diffuser sheet stretched sheet guide is provided with the light source. Independently movable structure.

Further, according to the present invention, the gate-shaped shape of the image pickup device fixing means is configured to have a shape substantially adapted to the cross-sectional contour of the object to be inspected.

Further, according to the present invention, the image pickup device fixing means includes a plurality of image pickup devices such as C
A CD camera is mounted, and the field of view of each of these CCD cameras is a continuous band along the cross-sectional contour of the surface to be inspected, and the moving direction of the object to be inspected and the horizontal or vertical direction in the image received by the CCD camera. Are configured to match.

Further, the present invention is configured such that the fields of view of the adjacent CCD cameras overlap in a region of a predetermined size.

In the present invention, the field of view adjustment and the focus adjustment of the CCD camera and the overlap amount adjustment may be performed in such a manner that the shape of the cross section of the object to be inspected is substantially adapted and the surface of the object has a line or a line at a predetermined interval. It is configured to use a reference model in which a predetermined figure such as a point or a grid line is drawn.

Further, according to the present invention, the reference model is configured to have a shape substantially adapted to the largest cross-sectional profile of the inspected object.

The present invention also relates to a reference model in which the ground on the surface of the reference model, that is, the color of the part other than the line of the figure is the color with the highest lightness in the paint color of the inspected object, for example, white or silver metallic. While imaging the surface,
The lens aperture and the shutter speed of the CD camera are adjusted.

The present invention also provides a test piece which is larger than the camera field of view painted with the paint color, is placed in contact with the surface of the reference model corresponding to the camera field of view and adjusts the lens aperture of the CCD camera while imaging it. It is configured to adjust the shutter speed.

Also, the present invention provides a method for controlling the speed of an object to be inspected and a conveyor for moving the object to be inspected at the time when the surface to be inspected is inspected after passing through the illuminating means and the image processing device fixing means. Are provided with speed matching means acting so as to match.

Further, according to the present invention, the inspection processing means may be arranged such that the spatial frequency component in the image data of the received light image obtained by the plurality of image pickup devices (CCD cameras) is in a high frequency region and the level is equal to or more than a predetermined value. Image enhancement means for extracting only the components of the following, and the result of continuously performing this processing on the moving inspected surface, as a result of which the moving amount of the inspected object and Tracking processing means for detecting an object whose moving direction matches under a predetermined condition;

Further, according to the present invention, the inspection processing means may start the inspection when the object to be inspected moves and start passing through the illumination means and the image processing device processing fixing means, and determine the end of the inspection after the inspection. Start / end determination means; and movement amount measurement means for measuring the movement amount of the object to be inspected with reference to the inspection start point, and the inspection surface of the object detected by the tracking processing means from information obtained from these. Calculate the upper position,
The result is displayed on the developed view of the inspected object.

Further, the present invention is configured such that the developed view of the object to be inspected is drawn based on the mounting angle and the angle of view of the imaging device with respect to the object to be inspected.

Further, the present invention is configured such that the inspection processing means performs an edge (isolated point) extraction process on a light-receiving image having a light and dark pattern obtained by the image pickup device fixing means by a scanning line parallel to the light and dark pattern.

In the present invention, the image pickup device processing fixing means may set the direction of the CCD camera in the direction of the cross section of the object to be inspected in the lateral direction (the number of pixels is large) of the CCD camera. An edge (isolated point) extraction process is performed on a light-receiving image having a light and dark pattern obtained by the image pickup device fixing means using a scanning line parallel to the light and dark pattern.

[0025]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a view showing a 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 front view of the present inspection apparatus. In FIG. 1, reference numeral 1 denotes an illuminating means, which is an arch (gate) -type illuminating device having an arc shape substantially matching the cross-sectional contour of the body 5. The illuminating means 1 is configured to project a predetermined light / dark pattern on the surface to be inspected. Reference numeral 2 denotes an image pickup device fixing means, which has substantially the same shape as the lighting means and is provided in parallel with the lighting means. Reference numeral 3 denotes an image pickup device such as a CCD camera, which is attached to and fixed to a predetermined number and position (not shown) of the image pickup device fixing means so as to pick up an image of the surface to be inspected on which the light and dark pattern is reflected. Reference numeral 4 denotes an inspection processing means, which mainly includes an image processing unit 41, a tracking processing unit 42, and a host computer 43.
Further, an edge (isolated point) extraction process is performed on a light-receiving image having a light and dark pattern obtained by the image pickup device fixing means using a scanning line parallel to the light and dark pattern. Reference numeral 10 denotes an inspection result output unit, which outputs a defect detection result detected by the inspection processing unit 4 by a printer.

The body 5 mounted on the carriage 6
Is moved on the rail 7 by the conveyor 8 in the illuminating device 1 and the image pickup device fixing means 2, at which time predetermined processing is performed by the inspection processing means 4, and the body 5, which is the surface to be inspected, is A defect detection inspection of the painted surface is performed.

FIG. 2 is a schematic top view of the present apparatus. As shown in FIG. 2, the positional relationship between the illuminating means 1 and the imaging device fixing means 2 is perpendicular to the transport direction of the body 5 (the direction of the arrow in the figure) and forms an arch shape. CCD
The camera 3 is adjusted to a predetermined position and angle by an image pickup device fixing means (hereinafter referred to as a camera stand) by an adjustment fixing jig 3 ′ having a structure (not shown) capable of freely adjusting the camera mounting position and angle. , Has been fixed.

FIG. 3 is a schematic side view of the present apparatus. FIG.
As shown in FIG. 5, the body 5 is placed on a trolley 6 with wheels 6 ', and moves on the rails 7 in the illuminating means 1 and the camera stand 2 by a conveyor 8 (not shown). Here, the shape of the illuminating means described in claim 2 will be described. The shape of the illuminating means is a shape substantially adapted to the cross-sectional profile of the object to be inspected (the body 5 in the present embodiment) as shown in FIG. With such a shape, the distance from the light irradiation surface of the illuminating means 1 to the surface of the object to be inspected becomes substantially constant irrespective of the region, and thus the light from the illuminating means 1 is uneven on the surface of the object to be inspected. Irradiation is almost uniform.

Next, the structure of the illuminating means according to claim 3 will be described. In order to irradiate the light of the light source to the inspected surface without waste and without unevenness, the illuminating means 1 includes a background plate on the back side of the light source which is white or surface-treated to diffusely reflect the light, and a plurality of light sources. The structure is such that they are attached at substantially equal intervals.

FIGS. 4 and 5 show an embodiment of the third aspect of the present invention. In the figure, reference number 101 is U
It is a tube-type fluorescent lamp, and is attached to the background plate 102 at substantially equal intervals. The lighting unit 104 is provided with four fluorescent lamps 101 mounted in two rows on one inspection object side of one background plate 102 and a power supply 107 (see FIG. 7) for high frequency lighting of the fluorescent lamps 101 mounted on the back side. I do. By attaching such a lighting unit 104 to a pillar 103 having an arch shape as shown in FIG. 5 without any gap, the lighting unit 1 can be realized.

Next, a method of forming a light and dark pattern in the illuminating means according to the fourth and sixth aspects will be described. FIG.
Is a light and dark pattern sheet and a sheet guide, FIG.
FIG. 5 is a schematic cross-sectional top view for explaining the positional relationship of the illumination unit components. In FIG. 6, reference numeral 105 denotes a sheet-like material, such as a matte black masking tape, which has a function of diffusing light and can be easily transformed into the cross-sectional contour shape of the inspection object. A predetermined light / dark pattern is applied. The reason for diffusing the light is to suppress the influence of the metallic glittering material when the painted body surface is metallic. Further, when the diffusion sheet 105 is made of a material that is apt to wrinkle, and the wrinkles cause shading or uneven illumination, as shown in FIG.
The generation of the wrinkles is suppressed by using the sheet guide 106 for supporting the object 05 from below and stretching the object to be inspected in the cross-sectional contour shape. The sheet guide 106 is painted in matte black, and the support of the sheet guide is
The intervals are set so as to overlap the dark portions of the 5 light and dark patterns. The sheet 105 and the sheet guide 106 are fixed by matting black bolts, nuts, washers, and the like at the support portions (not shown). Further, a caster 106 'is attached to the sheet guide 106 as shown in FIG. 6, so that the sheet guide 106 can be moved with the sheet 105 stretched. Therefore, if the lighting device 1 is free as shown in FIG. 5, the sheet guide 1 as shown in FIG.
Since 06 (dotted line in the figure) can move independently of the lighting device 1 (arrow in the drawing), for example, the fluorescent lamp 101 of the lighting device 1 can be easily replaced. The configuration of the lighting unit is not limited to the present embodiment.

Next, the details of the imaging device fixing means according to the seventh, eighth and ninth aspects will be described. FIG. 9 is a schematic view of the camera stand 2, and FIG. As shown in FIG. 9, the camera stand 2 has a shape substantially matching the cross-sectional profile of the body 5. This is camera 3
This is to make the distance from the camera to the surface of the body 5 substantially constant for all cameras. As a result, the size of the field of view for all cameras is substantially the same. The fine adjustment of the distance and the adjustment of the direction of the camera according to the body shape are performed by an adjustment fixture 3 ′ fixed to a predetermined position of the camera stand 2. In the case where the adjustment cannot be performed even with the adjustment fixing jig 3 ', for example, on the surface of the body 5 such as the hood (bonnet) and the roof (ceiling) where the height is greatly different, the focal length of the lens is changed to adjust the size of the camera field of view. May be. Further, as shown in FIG.
It is adjusted so as to have a band shape overlapping a predetermined size or more. As described above, the heights of the hood and the roof differ greatly, but as is clear from the figure, these parts are not inspected simultaneously by the same camera, so that the (H1 to H8) and the camera for the roof (R1 to R7) may be switched and adjusted. The switching position of the camera is suitably in the front and rear window portions which do not require inspection as shown in FIG. At this time, the field of view of the roof camera is different from that of the other side camera (SL1).
To SL5, SR1 to SR5) and the camera for the hood, the roof has a band shape as shown in FIG. Further, the overlap of the camera field of view is a region as shown by the hatched portion in FIG. However, there is also a problem that the number of cameras increases as the amount of overlap increases.
Therefore, the resolution of the image, that is, the size of the visual field per camera is determined from the minimum size of the defect to be detected,
From the size of the field of view, the approximate number of cameras required to inspect the entire surface to be inspected may be determined, and finally the overlap amount may be determined. Each camera field of view represented by a rectangle as shown in FIG. 10 is fixed without being inclined in a direction in which the body 5 moves in the horizontal or vertical direction in the image received by the camera.

Next, the speed matching means according to claim 14 will be described. FIG. 18 is a schematic view of an inspection line for explaining the speed matching means. An example of a mechanism in which the carriage 6 on which the body 5 is mounted is moved by the conveyor 8 will be described with reference to FIG. The transport conveyor 8 includes a chain 81, a driving device 82, and a hook 84. The pulse generator 83 detects rotation amount information of the driving device 82. The hook 8 is attached to the claw 61 at the bottom of the cart 6.
When the driving device 82 rotates in the direction of the arrow, the chain 81 is driven and the body 5 is transported. Therefore, if there is no gap between the claw 61 and the hook 84, the driving amount of the chain 81 and the driving device 82 and the moving amount of the body 5 substantially match.

In the camera stand 2 having the illuminating means 1 and the CCD camera 3 mounted and fixed at the above positions, the body 5 mounted on the carriage 6 is lowered by the transport conveyor 8 along the rail 7. It moves smoothly at a speed and without vibration, and at the same time, the inspection processing means 4 automatically detects a defect on the painted surface of the body in the procedure described below.

Next, the image enhancement means and the tracking processing means in the inspection processing means according to claim 15 will be described. FIG. 19 shows an example of an image and an example of a processing flow in the image enhancing means. FIG. 19A shows an image of the surface to be inspected on which the light and dark pattern is projected by the above-mentioned illuminating means. In the original image a, light is irregularly reflected at the concave-convex defect portion, and therefore appears as a dark portion in a bright pattern as shown in the figure. Similarly, when a defect exists in a dark pattern, it appears as a bright portion. When an edge detection process such as differentiation is performed on the original image a and binarized by a predetermined threshold value, an area having a luminance change, that is, an area having a high spatial frequency in the image as shown in FIG. A binary image in which white and other parts are black is obtained. This 2
Labeling (numbering) and area / centroid calculation are performed on the white pixels of the value image b. Since the defect is an isolated point in the white pixel of the binary image b and the boundary of the light and dark pattern is a large object that crosses the top and bottom of the screen, the area is determined with a predetermined determination value and only the isolated point with a small area is determined. Is extracted, an image as shown in FIG. 19C is obtained. If there are irregularities on the painted surface that do not cause defects such as citron skin,
As shown in FIG. 19C, an isolated point (hereinafter, referred to as a defect)
This is called noise) and may be extracted. In addition, when labeling (numbering) white pixels of the binary image b, as shown in FIG. 26, sequential labeling (numbering) is performed using scanning lines parallel to the light and dark pattern of a light-receiving image having a light and dark pattern. )
The labeling (numbering) processing time, that is, the isolated point extraction processing time is reduced. In the labeling (numbering), isolated points are numbered by observing light and dark runs (the number of start points and end points of the edge length) and their proximity. FIG. 27 shows a case where the direction of the camera is changed (perpendicular to the light / dark pattern) so that the scanning line of the labeling (numbering) processing is parallel to the light / dark pattern, and has the same effect.

A tracking process for extracting only a defect from such an image will be described with reference to FIGS. When the process of extracting isolated points is performed successively in time by the above-described image enhancing means, the area determination result image becomes as shown in FIG.
(A) to (f), and when these are overlapped, FIG.
(G). That is, since the camera and the illuminating means are fixed and the body as the object to be inspected moves, the defect on the body surface in the camera image moves in the direction of the arrow in FIG. Occurs randomly regardless of the movement of the body. Therefore, from the continuous area determination result images different in time, an image in which the moving amount and the moving direction of the body 5 match under the predetermined condition can be finally determined to be a defect. Since the moving direction of the defect in the image is determined by the direction in which the body passes with respect to the camera, if the camera position is fixed and the body transport direction is always the same as in the present embodiment, It can be determined for each camera. Furthermore, if the field of view of the camera is set parallel to the transport direction of the body 5 as described above in claim 8, the defect moves in the horizontal or vertical direction in the image. In the present embodiment, the defect is located right next to the image (arrow) as shown in FIG.
The following description is based on the assumption that the camera is fixed in such a direction as to move to the position.

In the two temporally successive images obtained in this manner, first, the barycentric coordinates in the y direction (vertical direction of the screen) of each white pixel of each image are compared. As described above, a defect moves right and left in an image. Therefore, if there is a white pixel having substantially the same y-axis barycenter coordinate between the two images, it can be determined that the white pixel is likely to be a defect. And stored in memory. Then x
As for the comparison of the directions, in the white pixels in the defect candidate, the difference between the barycentric coordinates in the x direction between the two images indicates the number of moving pixels in the image, and the sign indicates the moving direction. The actual number of moving pixels and the body moving direction in the image are compared and if they match within a predetermined range, it can be determined that the white pixel is more likely to be defective. , Y barycenter coordinates are stored. When the above series of processing is repeated and the number of times of the comparison in one white pixel is equal to or more than a predetermined number, the white pixel is determined to be defective (defect determination in the flow of FIG. 19). And store the final coordinates and area of the center of gravity. The tracking processing means performs the above-described processing continuously while the body is in the field of view of the camera, and sends the defect list to the host computer 43 after passing through the body.

Here, the actual moving pixel number can be calculated from the equation (1). Actual moving pixel number X = (inter-image time t × body moving speed v × image size L) / camera visual field A (1) inter-image time t: time difference between two temporally different images to be compared, In the present embodiment, this corresponds to the processing time of the image enhancement processing. This can be measured by counting the intervals at which the tracking processing means receives data (area / center-of-gravity coordinate data after area determination) from the image enhancement means. (Example: 0.1
[S]) Body moving speed v: The host computer 43 calculates from the rotation amount information of the driving device 82 of the pulse generator 83 and sends it to the tracking processing means as needed. (Example: 100 [mm
/ S]) Image size L: number of pixels in the body movement direction in the image.
For example, in the image of x × y = 512 × 480 pixels, the body is x
If moving in the direction, L = 512. Camera visual field A: Dimension of the camera visual field on the surface to be inspected in the body moving direction. For example, one camera field of view (rectangle in FIG. 10) on the surface to be inspected is x × y = 120 × 100 [m
m], if the body moves in the x direction, A = 120
[Mm].

Here, the relationship between the image time t, the body moving speed v, and the camera visual field A will be described. In the present embodiment, t corresponds to the image enhancement processing time. However, if the speed v is too fast to pass through the field of view A during the time t, if there is a defect, the same defect is included in the image. The above tracking process is not established because it does not appear more than once. Therefore,
The time t so that the defect is reflected at least twice in the image,
It is necessary to set the speed s and the field of view A.

If the timer is interrupted at predetermined time intervals and the above-mentioned image enhancement processing is executed, the time t becomes constant, so that the above-mentioned various adjustments and calculations become easy.

The image enhancing means and the tracking processing means are not limited to the present embodiment.

When the inspection of one body is completed by the inspection processing means as described above, a mark, for example, ● is placed at a position on the body development view corresponding to the defect position on the body surface based on the defect inspection result. indicate. This procedure will be described below.

First, the inspection start / end determining means and the movement amount measuring means according to claim 16 will be described. The inspection start / end determining means detects the movement of the body and determines the start / end timing of various inspection processes. For example, the transmission type photoelectric switch is moved in the direction perpendicular to the body transport direction, and the leading and trailing ends of the body are moved. This can be realized by mounting the photoelectric switch at such a height as to block the light of the photoelectric switch and at a position where the body blocks the photoelectric switch immediately before the front end of the body is reflected in the camera's field of view. If the relative positional relationship between the body 5 and the truck 6 is known, the photoelectric switch may be mounted in accordance with the truck.

As another embodiment, when the body is in the field of view of the camera and the body is reflected in the camera image,
The start / end timing of the inspection may be determined by using the difference in luminance of the image when there is no body and the background is reflected. The inspection start / end determination means is not limited to the present embodiment.

Next, the movement amount measuring means will be described.
The movement amount of the object to be inspected is measured based on the inspection start point detected by the inspection start / end determining means.
In the present embodiment, the movement amount is the pulse generator 8
The moving distance can be calculated from the rotation information of the driving device 82 obtained from Step 3 and time information such as the internal clock of the host computer 43. In other words, the inspection processing means 4 can always grasp the inspection position of the object to be inspected, and therefore can calculate the position of the defect detected by the tracking processing means on the body. And the position information on the body is stored in the list.

The above series of processing is executed for each camera image, and based on the list information of the detected defects, the display position in the developed view of the inspected object as shown in FIG. 21, for example, is calculated and marked. In FIG. 21, the defect display position in the y direction is the size of the camera field of view and the camera position is known, and the barycentric coordinate of the defect moving in the image in the y direction hardly changes. Once determined, it can be easily calculated. Similarly, the defect display position in the x direction can be calculated from the body movement amount based on the inspection start point in FIG. 21 as described above. The developed view in which the mark is displayed at the defect position is output to an output device such as a monitor or a printer.

Next, a reference model and various camera adjustment methods will be described. First, a reference model and various camera adjustment methods described in claim 10 will be described. FIG. 11 is a schematic front view, a top view, and a side view of a reference model 91 for door surface, hood / trunk, and door surface adjustment. FIG. 21 is a schematic diagram of a front view, a top view, and a side view of a reference model 92 for pillar surface and roof surface adjustment. The shapes of these reference models almost match the cross-sectional contours of the inspected object, as is clear from the figure. In the present embodiment, since the height difference between the hood surface and the roof surface of the vehicle body is large, the inspection is performed using separate cameras.
Are prepared, but the type of the reference model may be prepared according to the shape of the inspected object. Also, grid lines at predetermined intervals are drawn on the surface of the reference model as shown in the figure, and the camera field of view is adjusted as shown in FIG. 10 while each camera projects this grid line and checks it on a monitor. In other words, the grid lines need only be able to confirm the size of the camera's field of view,
Points at predetermined intervals as shown in FIG.
A figure such as a rectangle substantially the same as the size of the field of view determined in advance may be used. At this time, focus adjustment is also performed while looking at the figure of the reference model displayed on the monitor.

FIG. 13 shows the illumination means 1 at the time of the above adjustment.
FIG. 3 is a schematic top view showing a positional relationship between a camera, a camera, and a reference model. The body 5 to be inspected is a conveyor 8
Move along the rails 7 by the reference model 9
Is installed at the same position as the body 5 at the time of movement, that is, at a position 90 ° with respect to the rail and both ends of the reference model 9 coincide with the side surfaces of the body 5, and the camera 3 is adjusted.

FIG. 16 is a schematic front view showing the positional relationship between the illuminating means 1, the camera 3, and the reference model 91 when the hood / trunk surface and the door surface are adjusted. Similarly, FIG. 17 shows the roof surface and the pillar surface. It is a schematic front view at the time of adjustment. Body position during transport and reference model 9 as above
In order to make the positions 1 and 92 coincide with each other,
And various adjustments of the camera 3 are performed.

Next, the shape of the reference model will be described. As shown in FIGS. 11 and 12, the shape of the reference model must be substantially conforming to the cross-sectional contour of the body 5 to be inspected and conform to the outermost, that is, the contour of the largest cross-section of the body 5. Must. The fact that the cross-sectional profile is the largest means that the distance from the camera 3 is the shortest. If the field of view of the camera is adjusted in this state, the distance from the camera becomes long in other parts, so that the adjacent camera Will always exist. In other words, if the amount of overlap is adjusted in a state where the cross-sectional profile is not maximum, the view becomes smaller as the distance between the camera and the subject becomes smaller because the camera view section is triangular as shown in FIG. A predetermined overlap amount cannot be ensured in a portion having a horizontal cross-sectional profile. For this purpose, the reference model only needs to have a shape adapted to the largest cross-sectional profile of the object to be inspected. For the body 5 of the vehicle, for example, a door portion on the side, a roof center portion on the roof portion, a hood / trunk In the part, the highest part is suitable for the shape of the reference model.

FIG. 15 shows an example in which there are a plurality of types of bodies having different shapes. Body A as shown in FIG.
In cases B and B, the cross-sectional contours of the body A are larger in all parts, and therefore the reference models 91 and 92 are as shown by thick lines in the figure. As shown in FIG. 15B, when the size of the cross-sectional profile of the bodies A and B differs in each part, the bodies A and B
A shape like a bold line in the figure smoothly connecting the larger one of the cross-sectional contours.

Next, a camera adjustment method according to the twelfth and thirteenth aspects will be described. Since the distance from the camera to the surface to be inspected, that is, the imaging distance, changes depending on the shape and type of the object to be inspected, the depth of field of the camera (the range of focus) is necessary to focus in all cases. Needs to be sufficiently large with respect to the change in the photographing distance. Since the depth of field can be calculated from the lens aperture value, the lens focal length, and the shooting distance, if the lens specifications, the shooting distance, and the required depth of field are determined in advance from the size of the camera field of view, An approximate lens aperture value can be determined.

Further, the shutter speed of the camera is
When the inspected object is moving as in the present embodiment,
Since the value needs to be such that the image received by the camera is not blurred, the aperture and shutter speed may be finely adjusted and determined in consideration of the moving speed.

Hereinafter, a specific method of adjusting the aperture and the shutter speed will be described. The lens aperture and the shutter speed are adjusted using an oscilloscope or the like so that the output signal level of the camera does not saturate when the reflectance is the highest in the light reflection characteristic of the surface to be inspected. For example, when the object to be inspected is painted like an automobile body, the adjustment may be performed with the paint color having the highest brightness such as white or silver metallic. In addition, the reflection amount of the light,
The shorter the distance between the illumination and the camera and the surface to be inspected, the larger the reference model created from the maximum cross-sectional contour of the object to be inspected if the illumination and the camera position are fixed as in the present embodiment, for example. It is only necessary to make adjustments on the surface. As a guide for the above adjustment, in order to use the dynamic range in the brightness (luminance) direction without waste, the output signal level of the camera may be slightly before the white level exceeds the white level. Furthermore, in order to perform the above adjustment efficiently, the background part other than the figure of the surface on which the field adjustment figure of the reference model is drawn has the highest reflectance such as white or silver metallic as described above. If so, the adjustment can be performed together with the field of view adjustment of the camera.

When it is difficult to paint the adjustment surface of the reference model as described above, prepare a test piece larger than the camera field of view painted white or silver metallic as described above to correspond to the camera field to be adjusted. The adjustment may be performed while placing the camera in contact with the surface of the reference model to be imaged and capturing the image with a camera.

Next, the light and dark pattern according to claim 5 will be described. When edge detection based on differentiation is used in the image enhancement means, a change in luminance in the image is extracted, so that the boundaries of the light and dark patterns are also extracted as white pixels as shown in FIG. Therefore, if the defect is near the boundary between the light and dark patterns, the defect and the boundary may be integrated, and the defect may not appear as an isolated point. Furthermore, as the number of boundary lines reflected per screen increases, the frequency at which the defect disappears increases, so that the defect detection accuracy deteriorates. For example, since the front end of the front fender of the body 5 is a convex curved surface and acts as a convex lens, if the pitch of the light and dark pattern is constant regardless of the position,
The camera image will show more of the above boundary line than in the case of a flat part, and the defect detection accuracy will be degraded.

FIGS. 24 and 25 are explanatory diagrams of an embodiment for solving the above problem. In the figure, the dotted line indicates the position of the light and dark pattern sheet 105 reflected on the surface of the body 5 and reflected in the field of view of the camera 3, and an image example at that time is as shown in the figure. For example, in the image, there are four light-dark pattern boundaries.
In order to make this appear, the pitch of the light and dark pattern may be designed in consideration of the shape of the body 5 as shown in the figure. Here, the number of the boundary lines of the light and dark patterns is a problem, and there is no limitation since the way of displaying the light and dark patterns in the image, that is, the order of light / dark is not related to the detection principle using diffuse reflection at a defect. When the pitch of the light and dark pattern on the side surface of the body 5 is different from that on the horizontal surface as shown in the figure,
If a matte black tape is applied so that the light and dark pattern does not become discontinuous at the position where the light and dark pattern sheet shifts from the side surface to the horizontal plane, for example, at the R portion of the arch shape,
Even at the R portion between the front and rear fenders and the hood / trunk surface, the light and dark pattern can be projected without extreme distortion.

By the way, in FIGS. 24 and 25, the number of boundaries in the image is four, but the number of boundaries does not need to be the same in each camera. In addition, the frequency of defects appearing on the screen increases as the number of boundaries decreases, but if the pitch of the light and dark patterns is excessively widened in order to reduce the boundaries, it is small when detecting defects using irregular reflection due to irregularities in defects. Since the accuracy of defect detection is reduced, a light and dark pattern may be experimentally designed taking these factors into account.

Next, a development of the object to be inspected according to claim 17 will be described. Here, regardless of the shape of the body 5, the light / dark pattern of the illuminating means 1 is formed on the body surface reflected in the field of view of the CCD camera 3. That is, as shown in FIG. 23, the CCD camera 3 captures an image of the body 5 obliquely from the front.
The camera mounting angle at this time is θ2, and the camera angle of view is θ1.
And When the above inspection processing is performed at such a camera position and the defect position is displayed on a normal developed view as shown in FIG. 21, the defect position may not coincide with the actual defect position on the body. This is a view taken by the camera from a perspective obliquely forward as shown in FIG. 23, whereas the developed view is a view seen from the side of the body (side view) and from directly above (horizontal plane). This is because each viewpoint is different. In order to prevent the display displacement of such a defect, as shown in FIG.
May be used as a development view as viewed obliquely from the front like the actual camera 3. The rotation angle of the developed view at this time may be determined experimentally by the angles θ1 and θ2.

[0060]

As described above, according to the present invention, surface illumination light of a light and dark pattern is radiated from the periphery of the object to be inspected from the arch-shaped illumination means which is substantially adapted to the cross-sectional contour of the surface to be inspected. By using a plurality of imaging devices attached to a camera stand having an arched shape similar to the above, an image of the surface to be inspected, on which the light and dark patterns are projected, of the object to be inspected moving in the illumination means and the camera stand is obtained. An object having a predetermined area or less from each of the received light images and having the same moving amount and moving direction of the inspected object is determined as a defect,
By displaying the position of the detected defect on the developed view of the inspection object, the defect can be automatically and accurately detected without applying any control to the illumination means, the imaging device, and the inspection object. Can be obtained.

In the present invention, the field of view of the imaging means (camera) is such that adjacent fields of view overlap,
In addition, since a continuous band is formed, the entire surface to be inspected can be inspected without gaps. Further, by using the reference model having the largest cross-sectional profile of the object to be inspected, various adjustments of the camera can be performed accurately and easily in a short time.

In the present invention, the labeling (numbering) processing time, that is, the defect extraction processing time, is performed by sequentially performing labeling (numbering) using scanning lines parallel to the light-dark pattern of a light-receiving image having a light-dark pattern. By reducing the length, the effect that the processing time of the defect can be made faster can be obtained. Furthermore, by turning the cameras sideways, it is possible to reduce the apparatus cost by reducing the number of cameras.

[Brief description of the drawings]

FIG. 1 is a schematic front view of the present invention.

FIG. 2 is a schematic top view of the present invention.

FIG. 3 is a schematic side view of the present invention.

FIG. 4 is a schematic diagram of a part of a lighting unit 1 according to the embodiment.

FIG. 5 is an explanatory diagram of a positional relationship between the illumination means 1 and the body 5 in the embodiment of FIG.

FIG. 6 is a schematic perspective view of an example of a light and dark pattern sheet and a sheet guide of the illumination unit 1;

FIG. 7 is a schematic top view showing a positional relationship between the illumination unit 1, the imaging device 3, and the body 5.

FIG. 8 is an explanatory diagram showing movement of a light and dark pattern sheet.

FIG. 9 is a schematic front view showing an example of a mounting position of the camera 3.

FIG. 10 is an explanatory diagram of a camera field of view.

FIG. 11 is a diagram illustrating an example of a reference model for a hood / trunk surface and a door surface.

FIG. 12 is a diagram illustrating an example of a reference model for a roof surface and a pillar surface.

FIG. 13 is a schematic top view showing the positional relationship between the illumination means 1, the camera 3, and the reference model 9.

FIG. 14 is a view showing an example of a camera visual field adjustment graphic on the surface of a reference model 9;

FIG. 15 is a schematic front view for explaining the shape of the reference model 9;

FIG. 16 is a schematic front view illustrating an example of camera field-of-view adjustment using a reference model 91.

17 is a schematic front view illustrating an example of camera field-of-view adjustment using a reference model 92. FIG.

FIG. 18 is a schematic side view showing an example of the speed matching means.

FIG. 19 is a diagram illustrating an example of an image and a processing flow in an image enhancement unit and a tracking processing unit.

FIG. 20 is a diagram showing the movement of a defect in images different in time.

FIG. 21 is a diagram showing a camera field of view and a development view.

FIG. 22 is a diagram showing a development view with rotation added.

FIG. 23 is a schematic top view showing the camera mounting angle and the angle of view with respect to the body 5.

FIG. 24 is a schematic top view showing a light and dark pattern on the side surface of the body 5;

FIG. 25 is a schematic top view showing a light-dark pattern on the horizontal plane of the body 5;

FIG. 26 is a diagram illustrating a labeling processing scanning procedure in the first embodiment.

FIG. 27 is a diagram illustrating an example of a change in the direction of a camera according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination means 2 Imaging device fixing means (camera stand) 3 Imaging device (camera) 4 Inspection processing means 5 Body 6 Dolly 7 Rail 8 Conveyor 9 Reference model 10 Output printer 12 Defect generation source estimating means 41 Image processing unit 42 Tracking processing Unit 43 Host computer 61 Claw 81 Chain 82 Drive unit 83 Pulse generator 84 Hook 101 Fluorescent lamp 102 Background plate 103 Support 104 Lighting unit 105 Light / dark pattern diffusion sheet 106 Sheet guide 111 Vehicle type / paint type information input means 112 Defect number statistical processing means 113 Vehicle type detecting means 114 Body color detecting means

Claims (19)

[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 means for forming a predetermined light and dark pattern on the surface to be inspected in a gate shape surrounding the object to be inspected, and receiving light based on reflected light from the surface to be inspected in a portal shape surrounding the object to be inspected An imaging device fixing unit configured to attach a plurality of imaging devices for creating an image to a predetermined position; and detecting a defect on a surface to be inspected based on a received light image obtained from the imaging device and outputting a result. A surface defect inspection apparatus having an inspection processing means for inspecting a surface to be inspected when an object to be inspected moves and passes through the illumination means and the image pickup apparatus processing fixing means. 2. The surface defect inspection apparatus according to claim 1, wherein the gate-shaped shape of the illuminating means has a shape substantially adapted to a cross-sectional contour of the object to be inspected. 3. The surface defect inspection apparatus according to claim 1, wherein the illuminating means includes a plurality of light sources attached to the gate-shaped white background plate at substantially equal intervals. 4. A light-diffusing sheet having a matte black predetermined light-dark pattern formed inside the light source, that is, on the surface to be inspected, is disposed in the illumination means, and the light from the light source is diffused light in a light-dark pattern. The surface defect inspection apparatus according to claim 1, wherein the surface is illuminated and is illuminated on a surface to be inspected. 5. The surface defect inspection apparatus according to claim 1, wherein an interval between the light and dark patterns of the light and dark patterns changes based on the number of the light and dark patterns reflected on the CCD camera. . 6. The diffuser sheet has the same gate shape as the illuminating means and is covered with a matte black sheet guide.
The surface defect inspection apparatus according to any one of claims 1 to 4, wherein the sheet guide on which the diffusion sheet is stretched has a structure that can move independently of the light source. 7. The surface defect inspection apparatus according to claim 1, wherein the gate-shaped shape of the image pickup device fixing means is a shape substantially conforming to a cross-sectional contour of the object to be inspected. 8. A plurality of image pickup devices, for example, CCD cameras, are attached to the image pickup device fixing means in a direction for picking up an image of a surface to be inspected. The surface defect according to any one of claims 1 to 7, wherein the surface defect is a continuous band along the direction, and the moving direction of the object to be inspected coincides with the horizontal or vertical direction in the image received by the CCD camera. Inspection equipment. 9. The surface defect inspection apparatus according to claim 1, wherein the fields of view of the adjacent CCD cameras overlap in a region of a predetermined size. 10. The field-of-view adjustment and focus adjustment of the CCD camera and the overlap amount adjustment are performed with lines or points or grid lines having a shape substantially adapted to the cross-sectional contour of the object to be inspected and having a predetermined interval on the surface thereof. The surface defect inspection apparatus according to any one of claims 1 to 9, wherein the inspection is performed using a reference model in which a predetermined figure is drawn. 11. The surface defect inspection apparatus according to claim 1, wherein the reference model has a shape substantially conforming to the largest cross-sectional profile of the inspection object. 12. An image of the surface of the reference model in which the ground on the surface of the reference model, that is, the color of the portion other than the line of the figure is the color with the highest lightness in the paint color of the object to be inspected, for example, white or silver metallic. 11. The surface defect inspection apparatus according to claim 1, wherein a lens aperture and a shutter speed of the CCD camera are adjusted. 13. A test piece larger than the camera field of view painted with the paint color is placed in contact with the surface of the reference model corresponding to the camera field of view, and the lens aperture and shutter speed of the CCD camera are adjusted while capturing the image. The surface defect inspection apparatus according to any one of claims 1 to 10, wherein the inspection is performed. 14. When the inspection object surface is inspected after passing through the illuminating means and the imaging device processing fixing means, the speeds of the object to be inspected and the transport conveyor for moving the object to be inspected coincide. 2. The surface defect inspection apparatus according to claim 1, further comprising an operating speed matching unit. 15. The inspection processing means according to claim 1, wherein only a component having a high frequency region and a level equal to or higher than a predetermined value among spatial frequency components in image data of the received light image obtained by said plurality of imaging devices (CCD cameras). As a result of successively performing the image enhancement means to be extracted and this processing on the inspected surface to be moved, the moving amount and the moving direction of the inspected object can be determined from the successive images different in time by the same CCD camera. 2. The surface defect inspection apparatus according to claim 1, further comprising: a tracking processing unit that detects an object that matches under the following condition. 16. An inspection start / end determination means for starting inspection at the time when an object to be inspected moves and starts passing through the illuminating means and the imaging device processing fixing means, and judges the end of inspection after passing the inspection object. And movement amount measuring means for measuring the movement amount of the object to be inspected based on the inspection start point, and from the information obtained from these, the position of the object detected by the tracking processing means on the surface to be inspected is determined. 2. The surface defect inspection apparatus according to claim 1, wherein the calculation is performed, and the calculation result is displayed on a developed view of the inspection object. 17. The developed view of the object to be inspected is drawn based on an attachment angle and an angle of view of the imaging device with respect to the object to be inspected.
7. The surface defect inspection device according to any one of 6. 18. The method according to claim 1, wherein said inspection processing means performs an edge (isolated point) extraction process on a light-receiving image having a light and dark pattern obtained by said image pickup device fixing means by a scanning line parallel to the light and dark pattern. The surface defect inspection device according to the above. 19. The image pickup device processing fixing means sets the direction of the CCD camera in the direction of the cross section of the object to be inspected in the lateral direction (the number of pixels is large) of the CCD camera, and the inspection processing means fixes the image pickup device. 2. The method according to claim 1, wherein the light receiving image having the light and dark pattern obtained by the means is subjected to an edge (isolated point) extraction process using a scanning line parallel to the light and dark pattern.
A surface defect inspection device according to item 1.