WO2012164655A1

WO2012164655A1 - Automatic inspection device and automatic inspection method

Info

Publication number: WO2012164655A1
Application number: PCT/JP2011/062301
Authority: WO
Inventors: 昌年笹井
Original assignee: 株式会社メガトレード
Priority date: 2011-05-28
Filing date: 2011-05-28
Publication date: 2012-12-06
Also published as: JPWO2012164655A1

Abstract

[Problem] To provide an automatic inspection device that has been caused to not inspect regions at which inspection is unnecessary such as slits formed in a printed substrate, reducing false alarms as much as possible. [Solution] An automatic inspection device (1), which inspects printed substrates (10) having penetrated regions such as through holes (11), slits (12), or screw holes (13), and is provided with: an image acquisition means (2) that acquires an image of a printed substrate (10); a penetrated region extraction means (3) that extracts penetrated regions such as through holes (11), slits (12), and screw holes (13) from the acquired image; a post-elimination image extraction means (6) that extracts a post-elimination image of the printed substrate (10) having eliminated relatively small through holes (11) from among the extracted penetrated regions; and a shrinking processing means (7) that subjects the extracted post-elimination image of the printed substrate (10) to shrinking processing. It is possible to inspect only the shrinking processed region (A1).

Description

Automatic inspection device and automatic inspection method

The present invention relates to an automatic inspection apparatus for inspecting the formation state of pads, wiring patterns, silk, resist, etc. formed on a printed circuit board, and more specifically, among through holes, slits, screw holes, etc. formed on a printed circuit board. The present invention relates to an automatic inspection apparatus that does not inspect a relatively large slit or the vicinity of the edge of a screw hole.

Generally, pads, wiring patterns, silk, resist, etc. formed on a printed circuit board are inspected by an automatic inspection device.

By the way, when inspecting such a printed circuit board, the light emitted from the illumination device is received and inspected by the line sensor. Through holes, slits, screw holes, and edges of the printed circuit board are obtained from the illumination device. The light is regularly reflected, so it is easy to generate false alarms. Among these areas, through holes need to be inspected in detail, but there is no need for strict inspection in the vicinity of the edges of slits and screw holes. It is preferable not to inspect.

However, conventionally, when such a non-inspection area is set, there is only a method for setting the non-inspection area by the user (Patent Document 1, Patent Document 2, etc.). The area had to be set, and the work was very troublesome.

JP 2009-53197 A Japanese Patent Laid-Open No. 09-312318

Therefore, the present invention has been made in view of the above-mentioned problems, and by avoiding inspecting areas that are not necessary for inspection, such as the vicinity of slits formed on a printed circuit board, false information is reduced as much as possible. An object is to provide an automatic inspection device.

That is, the automatic inspection apparatus of the present invention acquires an image of a printed circuit board in an automatic inspection apparatus that inspects a printed circuit board having a through region such as a through hole, a slit, and a screw hole in order to solve the above problem. Means, through area extracting means for extracting through areas such as through holes, slits, screw holes and the like from the acquired image, and a print in which through areas smaller than a predetermined threshold are removed from the extracted through areas A post-removal image extracting unit for extracting an image after removal of the substrate; a contraction processing unit for contracting the extracted post-removal image of the printed circuit board; and an inspection unit for inspecting the contracted region. It is a thing.

With this configuration, small through holes can be inspected, and large slits and screw holes that do not need to be inspected, and the vicinity of the edge of the printed circuit board can not be inspected. By setting the inspection area, it becomes possible to reduce false alarms. In addition, when extracting an image after removal, in addition to extracting a through region smaller than a predetermined threshold and removing the small region, conversely, after removing by removing a through region larger than the predetermined threshold, etc. What is necessary is just to extract an image.

Further, in the case of extracting a penetrating region smaller than a predetermined threshold value, the circularity ratio, which is the ratio of the circular shape to the rectangular region, out of the penetrating region extracted by the penetrating region extracting means is used to exceed the predetermined threshold value. Also try to extract a small penetrating area.

This makes it possible to extract only the through holes that really need to be inspected, even when small vertically long slits and through holes are mixed.

According to the present invention, in an automatic inspection apparatus for inspecting a printed circuit board having a through region such as a through hole, a slit, and a screw hole, image acquisition means for acquiring an image of the printed circuit board, and the through hole from the acquired image A through region extracting means for extracting through regions such as slits, screw holes, and the like, and post-removal image extraction for extracting a post-removal image of the printed board from which the through regions smaller than a predetermined threshold are removed from the extracted through regions Means for contracting the image after removal of the extracted printed circuit board, and inspection means for inspecting the contracted region, so that small through holes can be inspected. Do not inspect large slits and screw holes that are not necessary for inspection, and the vicinity of the edge of the printed circuit board. Door can be. For this reason, it becomes possible to automatically set an inspection area and reduce false alarms.

Functional block diagram of an automatic inspection apparatus according to an embodiment of the present invention Drawing to extract the penetration area in the same form The figure which acquires the expansion picture in the same form Diagram for extracting through holes in the same form Diagram for extracting through holes in other forms The figure which acquires the image after the removal of the through hole in the same form The figure which sets the inspection area in the same form Flow chart showing processing in the same form

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The automatic inspection apparatus 1 according to the present embodiment can inspect the formation state of the printed circuit board 10, and is acquired by the image acquisition unit 2 that acquires an image of the printed circuit board 10 and the image acquisition unit 2. An inspection area A1 (see FIG. 7) is set from the obtained image, and the inspection area A1 can be inspected. Characteristically, the penetration area extracting means 3 for extracting the penetration areas such as the through holes 11, the slits 12, and the screw holes 13 from the image acquired by the image acquisition means 2, and the through area among the extracted penetration areas. A small penetrating region such as the hole 11 is extracted, and the post-removal image extracting means 6 for extracting the post-removal image from which the small penetrating region is removed, and the post-removal image are subjected to contraction processing. The inspection area A1 can be inspected. Hereinafter, the automatic inspection apparatus 1 according to the present embodiment will be described in detail.

First, the image acquisition means 2 acquires the surface image from the printed circuit board 10 which is an inspection object. When acquiring the surface image from the printed circuit board 10, the surface image may be acquired in gray scale. However, when inspecting the area inside the printed circuit board 10, the pad area where the metal is exposed is in gray scale. In addition, luminance changes such as a region where the resist is applied on the pad or a region where the resist is directly applied on the printed board 10 are not clear. For this reason, the surface image of the printed circuit board 10 is preferably acquired by RGB. When the surface image of the printed circuit board 10 is acquired by the image acquisition unit 2, light is emitted from an illumination device arranged obliquely above the printed circuit board 10, and the reflected light is reflected on a line sensor or The image is acquired by the area sensor, and the image is binarized with a predetermined threshold.

The penetrating region extracting means 3 extracts penetrating regions such as the through hole 11, the slit 12, and the screw hole 13 from the acquired image. When extracting this penetrating region, first, as shown in FIG. 2, an image of a stage for placing the printed circuit board 10 is acquired in advance, and the printed circuit board 10 and the stage acquired by the image acquisition means 2 are acquired. An image consisting only of the printed circuit board 10 is extracted by taking the difference from the image. At this time, the image consisting only of the printed circuit board 10 includes the through holes 11, the slits 12, the screw holes 13, and the pads and wiring patterns formed on the printed circuit board 10, silk, resist, and the like. Become.

Then, the extracted image of the printed circuit board 10 is expanded several pixels vertically and horizontally by the expansion processing means 4, and an image in which the through hole 11, the slit 12, and the screw hole 13 are blocked is obtained. When this expansion process is performed, the outer contour of the printed circuit board 10 is also expanded, and an image in which the outer contour is swollen is obtained. This will be described with reference to FIG. The upper diagram in FIG. 3 is an image of the printed circuit board 10 showing the extracted penetration region, and the lower diagram in FIG. 3 shows a state in which the image has been inflated (the broken line is the outer contour of the original printed circuit board 10). ). When this expansion process is performed, since the expansion process is performed in the direction in which the through hole 11, the slit 12, and the screw hole 13 are filled, in the expanded process, as shown in the lower diagram of FIG. This is an image in which the screw holes 13 are filled.

Next, the micro area extraction means 5 extracts a small through area such as the through hole 11 using the image expanded by the expansion processing means 4. When extracting this small penetrating region, various methods can be used. First, as shown in FIG. 4, as the first method, an image subjected to expansion processing by the expansion processing means 4 is expanded by the expansion rate. The shrinkage process is performed to restore the original size of the printed circuit board 10, and the difference between the shrinkage-processed image and the binarized image is obtained. At this time, in the contracted image, since the through region is filled, an image of the through hole 11, the slit 12, and the screw hole 13 is extracted by taking the difference. Then, in the extracted penetrating region, a ratio of the circular shape to the rectangular region surrounding the penetrating region (circularity ratio), an area, and a threshold value for the maximum length are set and smaller than those threshold values. A through region is extracted and a through region including only the through hole 11 is extracted.

As a second method, as shown in FIG. 5, the difference between the image extracted by the difference from the stage and the expansion image acquired by the expansion processing means 4 is taken, and the penetration formed in the printed circuit board 10. It is also possible to use a method of extracting an image consisting only of the through hole 11, the slit 12 and the screw hole 13 (shaded area in FIG. 5). At this time, a difference image having a very large area is obtained by expansion of the outer portion of the printed circuit board 10, and the slit 12 and the screw hole 13 have a relatively large area difference image, and the through hole 11 has a relatively small area. The difference image is obtained. Therefore, the outer portion of the largest printed circuit board 10 is excluded using the first threshold, and the smallest through hole 11 is smaller than the area of the slit 12 or the screw hole 13 and the through hole 11 An image consisting only of the through-holes 11 is extracted using a second threshold value that is larger than the area (the bottom diagram in FIG. 5).

As shown in FIG. 6, the post-removal image extracting unit 6 performs a process of adding the small penetrating region image extracted by the minute region extracting unit 5 to the obtained binarized image, and An image that does not exist (that is, an image in which only the large slit 12 and the screw hole 13 exist) is acquired. When this addition process is performed, the position or shape of the small penetrating area is acquired by the minute area extracting means 5, and the image at that position is added to the binarized image. Here, the images of the small penetrating areas extracted by the minute area extracting means 5 are added together, but the center position and diameter of the through hole 11 are extracted by the minute area extracting means 5 and the position and diameter are extracted. The image corresponding to may be removed from the binarized image. In this manner, the image of the small through hole 11 is removed by the post-removal image extracting means 6 and an image of the printed circuit board 10 including the relatively large slit 12 and screw hole 13 is obtained (FIG. 6 below).

Next, the contraction processing means 7 contracts the image having only the outer contour of the printed circuit board 10 and the slit 12 acquired in this way by several pixels toward the inside. Then, as indicated by the outer solid line of the hatched portion in FIG. 6, the outer contour of the printed circuit board 10 enters the inner side of the printed circuit board 10, and the opening width of the slit 12 and the screw hole 13 is also the contour of the slit 12. It enters the inside of the printed circuit board 10 so as to be large.

The inspection means 8 inspects the formation state of pads, wiring patterns, silk, resist, etc. of the printed circuit board 10 in the inner area A1 (outside the hatched area in FIG. 7) of the image subjected to the shrinkage process, and the shrinkage process is performed. The outer area A2 (shaded area in FIG. 7) of the image is not inspected. In this inspection, reference data is stored in advance, and the brightness value of the pixel of the image acquired from the printed circuit board 10 to be inspected is compared with the reference data, thereby forming the pad, wiring pattern, silk, resist formation state. Inspect.

Next, a method for setting the inspection area A1 and an automatic inspection method in the automatic inspection apparatus 1 configured as described above will be described with reference to the flowchart of FIG.

First, when inspecting the printed circuit board 10, an image of the stage on which the printed circuit board 10 is placed is acquired in advance, and an image of the printed circuit board 10 placed on the stage is acquired. And the image which consists only of the printed circuit board 10 is acquired from the difference of those images, and it binarizes (step S1).

On the other hand, the extracted image consisting only of the printed circuit board 10 is expanded to fill through regions such as the through holes 11, slits 12, screw holes 13 and the like (step S2), and contraction processing is performed again. The penetrating region is extracted by taking a difference between the images or by taking a difference from the binarized image acquired in step S1 (step S3).

Then, the circularity ratio, the area, the maximum length, etc. are calculated for the penetrating regions such as the through holes 11, the slits 12, and the screw holes 13 extracted in this way (step S4), and the penetrating regions smaller than the predetermined threshold ( Specifically, the region of the through hole 11) is extracted (step S5). At this time, the size and the size of the extracted penetrating region are also stored.

Next, the extracted region of the through hole 11 is added to the image acquired in step S1, and a post-removal image obtained by removing the image of the through hole 11 is acquired (step S6). At this time, the post-removal image is an image including relatively large slits 12, screw holes 13, and the like, as shown in the lower diagram of FIG.

Then, after the removal, the image is contracted inward (step S7), and the inner region A1 is inspected for the formation state of pads, wiring patterns, silk, resist, and the like (step S8).

As described above, according to the embodiment, in the automatic inspection apparatus 1 that inspects the printed circuit board 10 having the through regions such as the through holes 11, the slits 12, and the screw holes 13, the image acquisition unit that acquires the image of the printed circuit board 10. 2 and a through area extracting means 3 for extracting a through area such as the through hole 11, the slit 12, and the screw hole 13 from the acquired image, and a through area smaller than a predetermined threshold among the extracted through areas A post-removal image extracting means 6 for extracting a post-removal image of the printed circuit board 10 from which the image has been removed, a contraction processing means 7 for contracting the extracted post-removal image of the printed circuit board 10, and inspecting the contracted area The inspection means 8 is provided so that small through-holes can be inspected and large inspection is not required. Lit 12 and screw hole 13, the vicinity of the edge of the printed board 10 can be prevented from inspection. For this reason, it becomes possible to automatically set the inspection area A1 and reduce false alarms.

Further, if the post-removal image extracting means 6 extracts a penetrating area smaller than a predetermined threshold by using a circular ratio that is a ratio of a circular shape to a rectangular area, a small slit, a through hole, or the like is mixed. Even in such a case, a small slit is not extracted, and only the through hole 11 that really needs to be inspected can be extracted.

Note that the present invention is not limited to the above-described embodiment, and can be implemented in various modes.

For example, when extracting an image of the through hole 11, the slit 12, and the screw hole 13, since light does not reach the through hole portion and the portion tends to become dark, the luminance of the acquired image is dark. The portion may be extracted as a through hole 11 or a slit 12. Alternatively, when the through hole 11 is detected, if the diameter of the through hole 11 is known, the through hole 11 may be detected by pattern matching and only the image at that position may be extracted.

Further, in the above embodiment, the inspection is not performed on the slit 12, the screw hole 13, and the region A2 near the edge of the printed circuit board 10, but the region A2 is missing by a method different from the inspection region A1. Etc. may be inspected.

Furthermore, in the above embodiment, the through hole 11 is detected and the image of the through hole 11 is removed. However, an area having an area or a maximum length equal to or greater than a predetermined threshold (that is, a slit 12 or a screw). It is also possible to perform processing such as extracting the region 13 of the hole 13 and erasing other regions.

The present invention is used in a field where inspection is performed by setting a non-inspection area on a printed circuit board or a liquid crystal substrate.

DESCRIPTION OF SYMBOLS 1 ... Automatic inspection apparatus 2 ... Image acquisition means 3 ... Penetration area extraction means 4 ... Expansion processing means 5 ... Minute area extraction means 6 ... Post-removal image extraction means 7 ... Shrinkage treatment means 8 ... inspection means 10 ... printed circuit board 11 ... through hole 12 ... slit 13 ... screw hole A1 ... inspection area A2 ... non-inspection area

Claims

In an automatic inspection device that inspects printed circuit boards that have through areas such as through holes, slits, and screw holes,
Image acquisition means for acquiring an image of the printed circuit board;
A penetrating region extracting means for extracting penetrating regions such as the through hole, slit, screw hole and the like from the acquired image;
A post-removal image extraction unit that extracts a post-removal image of the printed circuit board from which the through region smaller than a predetermined threshold is removed from the extracted through region;
Shrinkage processing means for shrinking the image after removal of the extracted printed circuit board;
Inspection means for inspecting the contracted region;
An automatic inspection apparatus characterized by comprising:
2. The automatic inspection according to claim 1, wherein the penetrating region smaller than the predetermined threshold is a region extracted using a ratio of a circular shape to a rectangular region out of the penetrating regions extracted by the penetrating region extracting unit. apparatus.
In an automatic inspection method for inspecting a printed circuit board having a through region such as a through hole, a slit, and a screw hole,
Obtaining an image of the printed circuit board;
Extracting a through region such as the through hole, slit, screw hole and the like from the acquired image;
Extracting the post-removal image of the printed circuit board from which the through region smaller than a predetermined threshold is removed from the extracted through region;
Shrinking the image after removal of the extracted printed circuit board;
Inspecting the contracted region;
An automatic inspection method characterized by comprising:
The automatic inspection method according to claim 3, wherein the penetrating area smaller than the predetermined threshold is an area extracted using a ratio of a circular shape to a rectangular area in the extracted penetrating area.