JP2009085900A - System and method for testing component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the quality of an object under test, by initially performing a comparison of the object under test, by using an image as a template image which is obtained by photographing the state of the object under test, before being attached to its right place. <P>SOLUTION: A testing system is provided, wherein a template for performing an image comparison uses the image as the template image which is obtained by photographing the state of the object under test, before being attached to its right place, and the object under test is compared with it initially. Hence, an object that is excludable as being defective is actively excluded, and its test can be completed, as early as possible. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inspection method for automatically inspecting the mounting state of a component, and more particularly to a method for determining the presence or absence of an object by a pattern matching method.

In general, an image processing method using a pattern matching method is well known as a method for automatically recognizing a part mounting state of a product and automatically performing a quality determination. Usually, a template image for performing image comparison uses an image (image representing a correct state) captured in a state where a test object is attached at a correct position. Then, the template image and the image to be inspected are compared, and if the degree of similarity is high, it is determined that there is an object to be tested, and the quality is determined. In addition, as described in Japanese Patent Application Laid-Open No. 2001-148014 (hereinafter referred to as Patent Document 1), a method for automatically determining an optimal template without depending on knowledge and skill level, and other contrivances such as a color and an angle of illumination are devised. A device has been devised to increase the determination accuracy.
JP 2001-148014 A

  However, in this method, when the imaging state of the test object is easily affected by the brightness and the rotation angle, it is necessary to prepare an inspection environment such as blocking external light and improving the positioning accuracy of the test object.

  Also, since the detection accuracy of one template image is low, it is necessary to prepare a plurality of template images with various brightness and rotation angles, and to compare the images to be inspected multiple times. There was a problem that it took no time for judgment.

  An object of the present invention is to determine whether or not a test object is good by first comparing the test object with an image obtained by imaging the state before the test object is attached to the correct location. It is in.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The inspection system according to the present invention is for inspecting the product component mounting state, and includes an image processing device and a camera. The image processing device images the state before the test object is mounted at the correct location. An image is held as a template image at the time of fraud, and the template image at the time of fraud is compared with the image of the test object input from the camera.

  In addition, the inspection method for inspecting the component mounting state of the product related to the present invention by pattern matching prepares an image obtained by imaging the state in which no component is attached or an image obtained by imaging the state in which an incorrect component is attached as an improper template. Then, the image obtained by imaging the part to be inspected is compared with the template at the time of fraud, and when the similarity is larger than a predetermined threshold, it is determined that the part is not attached or the wrong part is attached. It is characterized by that.

  In addition, the preparation of an illegal template in this inspection method may be characterized in that an NG pattern is stored in the storage device of the image processing apparatus.

  The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

  According to the present invention, it is not necessary to prepare an advanced inspection environment, and it is inexpensive, and determination of quality can be made with high accuracy and quick determination time.

  In addition, since defect detection can be performed quickly and reliably, defect handling work in a later process and supply of alternative products can be performed at an early stage, thereby improving production efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Under the exterior check inspection system described in the embodiment of the present invention, pattern matching is performed by imaging the product appearance of an electronic device that has been assembled. When the target screw is not attached, the image processing apparatus has a mechanism for displaying an NG warning and prompting rework. Hereinafter, an inspection environment (inspection system) for exterior check according to the embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating an inspection system when performing an exterior check.

  The exterior inspection system including the object to be inspected includes an image processing apparatus 1, a camera 2, a positioning base 3, an object screw 4 to be inspected, an inspection object range 5 conceptually indicating an inspection object range, It consists of an electronic device 6 that is a specimen.

  FIG. 2 is a diagram showing an exterior check method for electronic apparatus 6 using a template image and a comparison method with a product image in the embodiment of the present invention. FIG. 3 is a diagram showing a method for creating the template image used in FIG.

  In FIG. 2, NG pattern templates 8 (1), 8 (2), OK pattern templates 9 (1), 9 (2), 9 ( 3) is described.

  The image processing apparatus 1 determines an approximation between the product image 7 captured by the camera 2 and the NG pattern templates 8 (1), 8 (2) and the OK pattern templates 9 (1), 9 (2), 9 (3). Then, based on the closest image, it is determined whether or not the attachment of the target screw 4 is normal.

  The NG pattern template 8 (1) is related to forgetting to attach the target screw 4, and the NG pattern template 8 (2) is a case where an incorrect screw is used as the target screw 4.

  On the other hand, the OK pattern template 9 (1) is an example in which the screw hole 10 of the target screw 4 is not inclined and the light source is provided on the upper right. The OK pattern template 9 (2) is an example in which the screw hole 10 of the target screw 4 is not inclined and the light source is provided at the upper left. The OK pattern template 9 (3) is an example in which the screw hole 10 of the target screw 4 is inclined and a light source is provided on the upper right.

  FIG. 4 is a diagram showing preparation of an NG pattern target image (unauthorized target image) and an OK pattern target image in the embodiment of the present invention. FIG. 5 is a diagram showing a range in which a threshold for determining pass / fail of inspection can be set when an OK pattern template image is applied in the embodiment of the present invention. Here, the target image refers to an image for determining a threshold value for determining pass / fail of inspection when a template image is used.

  FIG. 6 is a diagram showing a comparison method with a product image when the OK pattern template 9 is applied in the embodiment of the present invention, and FIG. 7 is a method for creating the NG pattern template 8 in the embodiment of the present invention. FIG. FIG. 8 is a schematic diagram showing a range in which a threshold for determining pass / fail of inspection can be set when the NG pattern template 8 is applied in the embodiment of the present invention.

  With reference to these drawings, a template image preparation required for pattern matching and an inspection pass / fail determination method will be described below.

(Conventional technology)
First, the flow of work when applying the inspection pass / fail determination method using only the OK pattern templates 9 (1) to (3), which is the prior art, will be described.

  First, the electronic device 6 is prepared and placed on the positioning base 3. Next, the screw 4 to be inspected is attached and imaged by the camera 2.

  A portion of the inspection target range 5 is cut out from the captured image, and an OK pattern template 9 is created. At this time, depending on the mounting state of the target screw 4, the angle of the screw hole 10 is varied, and the surface of the target screw 4 is close to a mirror surface. 11 effects are considered.

  For these measures, as shown in FIGS. 2 and 3, the screw hole 10 has a plurality of angle patterns such as the screw hole 10 (1) and the screw hole 10 (2), and the reflected light 11 has a reflected light 11 ( A plurality of OK pattern template images 9 are prepared by combining light source position patterns that reproduce a plurality of reflected lights 11 such as 1) and reflected light 11 (2).

  Next, a target image is prepared in order to determine a threshold value for determining pass / fail of the inspection when the template image is used. At this time, the product to be inspected is considered to be slightly different from each other due to differences in assembly workers, material dimensional errors, etc. Prepares electronic devices 6 of the same model but with different product numbers and places them on the positioning base 3.

  Thereafter, as shown in FIG. 4, imaging is performed in a state where the target screw 4 is not attached to the electronic device 6, and an NG pattern target image 12 is created. Further, an image is taken with the target screw 4 attached to the electronic device 6 to obtain an OK pattern target image 13.

  Thereafter, the similarity with the OK pattern target image 13 and the similarity with the NG pattern target image 12 are acquired with respect to the OK pattern template 9.

  Based on the similarity obtained as described above, as shown in FIG. 5, a threshold setting possible range 14 for determining the pass / fail of inspection when the OK pattern template 9 is used is acquired. Then, the operator who operates the inspection environment determines the threshold within the range of the threshold settable range 14 in the OK pattern template 9. If the degree of similarity with the NG pattern target image 12 is 50% and the degree of similarity with the OK pattern target image 13 is 70%, a threshold value is set at an intermediate 60%.

  The OK pattern template 9 and threshold data prepared as described above are input to the image processing apparatus 1 so that the product appearance check can be performed.

  Next, an assembled electronic device 6 to be inspected is prepared, placed on the positioning base 3, and imaged by the camera 2 to obtain a product image 7 of the electronic device 6. Thereafter, pattern matching is performed, and the degree of similarity between the OK pattern template 9 (1) and the product image 7 is acquired as shown in FIG. 6, and if the degree of similarity exceeds the threshold, it is determined that the target screw 4 is present and the inspection OK. Display.

  If the similarity is below the threshold, the similarity between another OK pattern template 9 (2) and the product image 7 is acquired and compared with the threshold. If the similarity exceeds the threshold, it is determined that the target screw 4 is present. The inspection OK is displayed.

  When the above processing is repeated and the similarity between all registered OK pattern templates 9 and the product image 7 is below the threshold value, it is determined that there is no target screw 4 and an NG warning is displayed. Make a visual check.

(Technology related to the present invention)
However, when the electronic device 6 is inspected in the exterior check environment after the above preparation, all of the electronic devices 6 that are in the state of receiving the inspection NG determination because the target screw 4 is not attached are all inspected. The inspection NG determination is not made unless the pattern matching process with the OK pattern template 9 is completed. Therefore, as the quantity of the OK pattern template 9 is larger, it takes time until the inspection NG determination.

  In the present invention, by introducing the inspection pass / fail determination method using the NG pattern template 8 to the appearance check device, the electronic device 6 to be the inspection NG can be extracted early. The work flow associated with the application of the present invention will be described below.

  First, in order to prepare the NG pattern templates 8 (1) and (2), the electronic device 6 is prepared, placed on the positioning base 3, and imaged by the camera 2. A portion of the inspection target range 5 is cut out from the captured image, and an NG pattern template 8 is created.

  At this time, the pattern of the operation NG includes a situation where the target screw 4 is not attached and a situation where the other type screw 16 is attached. In order to cope with these, as shown in FIG. 7, only the screw hole 15 is imaged to prepare the NG pattern template 8 (1). Further, if it is easy to identify the screw head of the other type screw 16 being flat or the like, an image is taken with the other type screw 16 attached instead of the target screw 4 to prepare the NG pattern template 8 (2).

  Next, the threshold value is examined using the target images mentioned in the description of the conventional technique. First, the similarity between the NG pattern template 8 and the target image 13 having the OK pattern is acquired, and then the similarity between the NG pattern and the target image 12 is acquired.

  Based on the similarity obtained as described above, as shown in FIG. 8, a threshold setting possible range 17 for determining pass / fail of inspection when the NG pattern template 8 is used is acquired. Then, the threshold value is determined within the range of the threshold setting possible range 17 in the NG pattern template. If the degree of similarity with the NG pattern target image 12 is 90% and the degree of similarity with the OK pattern target image 13 is 50%, the threshold value is set to an intermediate 70%. This process is performed for all the NG pattern templates 8.

  The NG pattern template 8 and threshold data prepared as described above, and the OK pattern template 9 and threshold data described in the prior art are input to the image processing apparatus 1 to enable a product appearance check. . Next, an assembled electronic device 6 to be inspected is prepared, placed on the positioning base 3, and imaged by the camera 2 to obtain a product image 7 of the electronic device 6. Thereafter, pattern matching is performed as shown in FIG.

  First, the NG pattern template 8 and the product image 7 are compared. As a method, the similarity between the NG pattern template 8 (1) and the product image 7 is acquired, and if the similarity exceeds a threshold, it is determined that there is no target screw 4 and an NG warning is displayed. If the similarity is below the threshold, the similarity between another NG pattern template 8 (2) and the product image 7 is acquired and compared with the threshold. If the similarity exceeds the threshold, it is determined that there is no target screw 4. An NG warning is displayed.

  When the above processing is repeated and the similarity between all the registered NG pattern templates 8 and the product image 7 is lower than the threshold value, the inspection pass / fail determination process using the OK pattern template 9 which is the conventional technology is performed, If all similarities are below the threshold, visual confirmation by the operator is performed.

  By completing the above preparation, when the electronic device 6 is inspected in the exterior check environment, the target screw 4 is not attached or another type of screw 16 is attached. When the electronic device 6 in the situation is inspected, the inspection NG is judged early regardless of the quantity of the OK pattern templates 9.

  The pattern matching method according to the present invention is particularly effective when the article to be inspected is an article that is easily affected by the mounting angle and illumination light, such as the target screw 4 described in the embodiment.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

  The present invention is a method that can automatically and quickly detect forgetting to attach a part, and is a method that can be practically used in all processes in the field of assembly work.

  It can also be used in the process of confirming the presence or absence of scratches, and the application field is considered wide.

It is a figure showing the environment at the time of performing the exterior check concerning this invention. It is a figure which shows the exterior check method of an electronic device, and the comparison method with a product image. It is a figure which shows the preparation method of an OK pattern template. It is a figure which shows the preparation of the NG pattern target and OK pattern target which are used in order to determine the threshold value of inspection pass / fail. It is a schematic diagram which shows the range which can set the threshold value for determining a test | inspection pass / fail at the time of applying an OK pattern template. It is a figure which shows the comparison method with a product image at the time of applying an OK pattern template. It is a figure which shows the preparation method of the NG pattern template in embodiment of this invention. It is a schematic diagram which shows the range which can set the threshold value for determining a test | inspection pass / fail at the time of applying NG pattern template in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 2 ... Camera, 3 ... Positioning base, 4 ... Target screw,
5 ... Inspection target range, 6 ... Electronic equipment, 7 ... Product image,
8 (1) (2) ... NG pattern template,
9 (1) (2) (3) ... OK pattern template, 10 ... Screw hole, 11 ... Reflected light,
12 ... NG pattern target image, 13 ... OK pattern target image,
14 ... Threshold setting range, 15 ... Screw hole,
16 ... Other product screws, 17 ... Threshold setting range

Claims (3)

In an inspection system that includes an image processing device and a camera, and inspects the product component mounting state,
The image processing apparatus holds an image obtained by imaging a state before the test object is attached to a correct location as a template for fraud.
The image processing apparatus compares the improper template with an image of a test object input from the camera.   In the inspection method for inspecting the part mounting state of a product by pattern matching, prepare an image that captures the state where the part is not mounted or an image that captures the state that the wrong part is mounted as an improper template. Comparing an image obtained by imaging a part with the template at the time of fraud, and determining that a part is not attached or an incorrect part is attached when the similarity is greater than a predetermined threshold Inspection method.   3. The inspection method according to claim 2, wherein the preparation of the unauthorized template includes storing an NG pattern in a storage device of an image processing apparatus.

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