JPS5811839A - Flaw detector - Google Patents

Abstract

PURPOSE:To decide on the presence of a flaw easily by shooting a body to be inspected in at least two side directions, recording reflection parts of those images as binary data on every picture element, and ANDing those data. CONSTITUTION:A luminaire 9 emits a laser beam 19 to a body to be inspected (microswitch) 1 slantingly above its rear part (in direction B), and the object is shot by a camera 10 to binary-coding the image 20 on picture element unit basis through a binary coding circuit 11, thus obtaining a binary-coded image. This image has diffused reflection at positions which correspond to a crack 4, a fragment, and an edge part 7 of the body 1 to be inspected and these parts are brigher than any other part, which is utilized to regard the diffused reflection part in the image [1] and other parts as [0], thereby binary-coding every picture element. Said binary-coded image is stored in a storage circuit 12. Similarly, the body 1 to be inspected is further irradiated with the beam 19 slantingly above the rear part (in directin C) to obtain a binary-coded image, which is stored in a storage circuit 13. The image in the circuits 12 and 13 are transferred to an AND circuit 14 to AND data of the same addresses, obtaining a binary-coded image for flaw discrimination.

Description

[Detailed description of the invention] This invention relates to a flaw detection device.

Conventionally, in order to detect cracks or chips on the surface of a microswitch, as shown in FIG. I was doing it by grasping it. However, as shown in FIG. 2 (a diagram showing an image 6 taken by the camera 5 when the microswitch 1 is irradiated with light from the direction of the arrow A), the diffused reflection of the spot light 3 occurs only at the crack 4. However, this also occurs at the edge portion 7, so it is necessary to improve the positioning accuracy of the microswitch 1 and cover the edge portion 7 with a mask 8 to extract only the diffusely reflected light from the crack 4.
The problem is that the high-precision positioning work and the masking work for the edge portion 7 are complicated.

Therefore, an object of the present invention is to provide a flaw detection device that can omit the work of highly accurate positioning of the object to be inspected and the work of masking the edge portions.

An embodiment of the present invention will be described with reference to FIGS. 3 to 6. That is, this flaw detection device includes a lighting device 9 and a camera 10 arranged above the microswitch 1 as shown in FIG. 3, and a binarization circuit 11 as shown in FIG.
Memory circuits 12, 13° AND circuit 14 and pass/fail! l'
An lJ constant circuit 15 is provided.

The illumination device 9 consists of a Rede beam projector 16, an oblique mirror 17 rotatable around a vertical axis, and a reflector [8] formed by cutting a parabolic concave mirror into an annular shape. 1
The radar beam 19 projected vertically downward from the mirror 17 is reflected by the diagonal mirror 17, and is further reflected by the reflector 18 to irradiate the microswitch 1 diagonally from above.By rotating the diagonal mirror 17 around the vertical axis, the laser beam is The direction of irradiation of the light beam 19 onto the microswitch 1 can be freely changed.

To detect scratches, use the illumination device 9 as shown in FIG.
As shown in a), the radar beam 19 is irradiated diagonally upward from the rear of the microswitch 1 (in the direction of arrow B), and the camera 1 is
0, and the image 2o is converted into 21i& for each pixel by the binary value circuit 11 to obtain the binary image 21 shown in FIG. 6(a). This binarized image 21 is created by taking advantage of the fact that diffuse reflection occurs at the chatter 4 and chip 22 joint part 7 of the microswitch 1, and that part shines brighter than other parts. It is obtained by binarizing each pixel with the non-diffuse reflected light part as "1" and "0". In Fig. 6(a), 23 is the data due to the crack 4, and 24 is the data due to the chip 22. , 25 is the data from the edge portion 7. Binarized image obtained in this way @
21 is stored in the memory circuit 12.

Next, the oblique mirror 17 is rotated 180 degrees, and as shown in FIG. The microswitch 1 is photographed by the camera, and the camera image 26 is binarized for each pixel by the binarization circuit 11 to obtain a binarized image 27 shown in FIG. 6(b), which is stored in the storage circuit 13. let

In this case, in the binarized image 27, 28 r/'i data is due to the crack 4, 29 is data due to the chip 22, and 30 is data due to the edge portion 31.

Then, the 2
The digitized images 21 and 27 are input to the AND circuit 14, and the AND circuit 14 calculates the AND of the same addresses of both the binarization circuits 21 and 27 to determine the flaw as shown in Figure 6 (C). Obtain a binary image: ) 2. In this case, the position of diffuse reflection due to the crack 4 or chip 22 does not change even if the light irradiation direction changes,
Since the position of diffused reflection by the edge portions 7 and 31 changes when the light irradiation direction changes, data 33 due to the crack 4 is included in the binary image 32 for flaw determination obtained by logical product of both the binary images 21 and 27. Only data 34 due to missing 22 remains,
All data due to edge portion 7.31 will be erased. Then, this binary image 32 for flaw determination is inputted to the quality determination circuit 15, and in this quality determination circuit 15, data 33. If 34 is cut, it is "defective"
If the data 33.34 does not remain, it is "good".
It is determined that flaws such as crack 4 and chip 22 are detected.

In this way, since the binary images 21 and 27 obtained when the microswitch 1 is irradiated with light from two directions are logically ANDed, the edge portion is not included in the binary image 32 for flaw determination (5). 7,31 data 25° 30 is erased and data 33.34 due to cracks 4 and chips 22
This remains and is sent to the pass/fail judgment circuit 15 to detect flaws, making it possible to omit the conventional high-precision positioning work and masking work to erase the data on the edge portion 7.31. . Furthermore, the configuration of the device is extremely simple. Further, by repeating the logical product of the binary images 21 and 27 obtained by irradiating light from 180 degrees different directions many times, the flaw detection accuracy can be improved.

Note that the illumination device 35 in FIG. 7 may be used instead of the illumination device 9 in FIG. 3. This illumination device 35 sequentially emits strobe spot light from opposing light sources 36, and any set of light sources 36 is prepared. When this illumination device 35 is used, each time each light source 36 emits light, a binarized image is obtained by the binarization circuit 11 and sequentially stored in the memory circuits 12 and 13. By inputting it to the pass/fail judgment circuit 15, flaws can be detected without performing the high positioning work of the microswitch 1 and the masking work of the edge portions 7 and 31, as in the embodiment (6) above. ,.

As described above, the flaw detection device of the present invention includes: an illumination device that can freely irradiate light from at least two directions on both sides of an object to be inspected; a camera that photographs the object to be inspected illuminated by the light; A binarization circuit that obtains a binarized image by binarizing each pixel with the diffuse reflection part of the image as "1" and the extraordinary emitted light part as "()"; first and second storage circuits that respectively store the obtained binarized images;
It is equipped with an AND circuit that takes the AND of the memory contents at the same address in the memory circuit of the AND circuit, and a pass/fail judgment circuit that determines the presence or absence of flaws on the inspected object based on the presence or absence of an output signal from this AND circuit. This has the effect of omitting the work of high-precision positioning of objects and the work of masking edges.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional example, FIG. 2 is a diagram showing a camera image, FIG. 3 is a perspective view of an illumination device used in an embodiment of the present invention, and FIG. 4 is a block diagram of this embodiment. Figure 5(a)
, (b) are diagrams showing camera images when the microswitch is irradiated with laser light, and Figure 6 (a) is
, (b) is a diagram showing the binarized image, and FIG. 6 (C) is the logical AND of @! l! FIG. 2 is a perspective view of a binarization device for J-standard binary values and others. DESCRIPTION OF SYMBOLS 1... Micro switch (test object), 4... Crack, 9, 35... Lighting device, 10... Camera, 11...
...Binarization circuit, 12.13...Memory circuit, 14...
・Logic product circuit, 15... Pass/fail judgment circuit, 20.26・
...Camera image, 21, 27...Binarized image, 22.
・・Chip - 1 piece -] D

Claims (1)

[Claims] An illumination device that can freely irradiate light from at least two directions on both sides of the object to be inspected, a camera that photographs the object to be inspected illuminated by the light, and a diffusely reflected light portion of the image taken by this camera
'' and binarizing each pixel by setting the extraordinary emitted light portion to ``0'' to obtain a binarized image, and each of the above-mentioned binarized images obtained by changing the irradiation direction of the spot light. an AND circuit that takes the AND of the storage contents at the same address in the first and second storage circuits, and an output signal from the AND circuit. A flaw detection device includes a pass/fail judgment circuit that determines the presence or absence of flaws on an object to be inspected based on the presence or absence of flaws.