JP2011047697A - Visual inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual inspection device capable of rapidly detecting problems by transmitting defect information such as the number of occurred defects in an easily understood manner. <P>SOLUTION: The visual inspection device includes a camera 2 for photographing an inspection target surface of an inspection target 10, and an image processing device 1 which is connected to the camera 2 and determines the quality of the inspection target 10 based on a picture signal from the camera 2. The image processing device 1 detects defect pixels by performing image processing on image data, performs quality determination based on an inspection condition C1, and stores positional information of the defect pixels, image data and the result of quality determination. The image processing device 1 includes a device body 1b and a monitor 1a. The device body 1b calculates the frequency of defect occurrence based on the positional information of the stored defects, changes at least one of the density and hue of pixels in a pixel region of a designated defect occurrence frequency, and displays it overlaid on an image of the inspection target 10. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an appearance inspection apparatus that inspects a defective item in the appearance of an object based on an inspection image obtained by imaging the inspection object.

  2. Description of the Related Art Conventionally, there is an appearance inspection apparatus that detects the presence or absence of defects on the appearance of an inspection object by performing image processing on image data obtained by imaging the inspection object and determines whether the inspection object is good (for example, Patent Document 1).

  The defect inspection apparatus described in Patent Document 1 irradiates illumination light from a light source obliquely onto an inspection object, and an imaging apparatus such as a CCD camera having an optical axis in a direction different from the irradiation direction of the illumination light. To image the inspection object. An image captured by the imaging device is converted into a digital signal by an A / D converter, and noise is removed by image calculation processing such as differential calculation, and a pixel group having a high degree of coincidence with a defective portion is defined as a defect candidate land. Extract. The number of pixels included in the defect candidate land is compared with a predetermined threshold value to determine the presence / absence of a defect, and the quality of the inspection object is determined.

JP 2000-339462 A

  By the way, in the defect inspection apparatus as described above, a display unit such as a liquid crystal display is connected for the purpose of the user confirming the determination result of pass / fail determination. The display means includes the total number of inspection objects that have been inspected, the ratio of non-defective products and defective products, the number of defects generated in the inspection objects, and the occurrence of defects in each area by dividing the inspection object into a plurality of areas. Defect information such as number and frequency of occurrence is displayed. Based on the defect information, the user grasps the cause of the defect and problems on the production line, and takes measures such as adjusting various devices constituting the production line and changing inspection conditions used for pass / fail judgment.

  However, in the conventional defect inspection apparatus, defect information such as the number of occurrences of defects in each area is mainly displayed as character information, and deep knowledge and experience are required to detect and respond to problems from character information. As a result, there was a problem that the response was delayed and the product was wasted.

  The present invention has been made in view of the above-mentioned reasons, and the purpose of the present invention is to provide an appearance that can quickly detect a problem by easily transmitting defect information such as the number of occurrences of defects. It is to provide an inspection device.

  In order to achieve the above object, according to the first aspect of the present invention, an imaging means for imaging an inspection object, and image data obtained by imaging the inspection object by the imaging means are used for the object. A defect location detection unit that detects the number and position of defective pixels that exist, a storage unit that stores the number and position of defective pixels detected by the defect location detection unit, and a plurality of inspection objects stored in the storage unit A calculation unit that calculates a defect occurrence frequency for each pixel region including a predetermined number of pixels based on the number and position of defective pixels in the pixel region, and a pixel region having a specified occurrence frequency based on a calculation result of the calculation unit And a display means for displaying at least one of the shading and the hue of the pixel so as to overlap the image of the inspection object.

  According to a second aspect of the present invention, in the first aspect of the present invention, the display unit displays a pixel region in which the number of consecutive occurrences of defects in the same pixel region matches the designated number of consecutive occurrences. It is characterized in that at least one of the above is changed and displayed on the image of the inspection object.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, a plurality of inspection conditions relating to the number and position of defective portions are set, and an inspection for determining whether the inspection object is good or not based on each inspection condition And the display means displays the defect occurrence frequency so as to overlap the image of the inspection object when the determination results of the quality determination based on the plurality of inspection conditions differ.

  In invention of Claim 4, in the invention as described in any one of Claims 1-3, the said display part is based on the number and position of the defective pixel in the some test object memorize | stored in the said memory | storage part. Image data including a pixel region having a calculated occurrence frequency equal to or higher than a predetermined frequency is displayed.

  According to the first aspect of the present invention, the pixel area having the specified occurrence frequency of the defect is displayed on the image obtained by imaging the inspection object while changing the shade or the hue of the pixel. Thus, the position and frequency of the specified occurrence frequency defect can be communicated to the user in an easy-to-understand manner, and the cause can be quickly identified and measures such as production line adjustment and inspection condition change can be performed at an early stage.

  According to the invention of claim 2, in the inspection object that has been continuously judged to be good or bad, it is possible to early detect a defect that has continuously occurred in the same pixel region, and to identify the cause Becomes easier.

  According to the invention of claim 3, it is easier to determine the reference value when changing the inspection condition by displaying the occurrence frequency of the defect only when the determination result of the pass / fail determination is different depending on a plurality of inspection conditions. Efficient inspection conditions can be set.

  According to the invention of claim 4, by displaying image data including a defective portion having a high frequency, an inspection object having a high possibility of including a defect is actually confirmed, and the presence or absence of a problem is more accurately grasped. be able to.

1 is a schematic configuration diagram of an appearance inspection apparatus according to an embodiment of the present invention. The display contents in the inspection apparatus are shown, in which (a) is a reference image of an inspection object, and (b) to (f) are examples of the defect image.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an appearance inspection apparatus according to the present invention is connected to a camera 2 that images an inspection object 10 and the camera 2, and determines whether the inspection object 10 is good or bad based on a video signal from the camera 2. The image processing apparatus 1 is provided.

  This appearance inspection apparatus constitutes a production line for the inspection object 10 together with other production apparatuses (not shown) including, for example, a belt conveyor. The inspection object 10 is transported in a certain direction by, for example, a belt conveyor, and is set so that the inspection surface of the inspection object 10 is on the camera 2 side at a predetermined position of the appearance inspection apparatus. The appearance inspection apparatus detects a defective portion of the inspection object 10, performs a pass / fail determination based on the number and positions of the defective portions, and outputs a determination result of the pass / fail determination to an equipment control device that controls the production apparatus. The inspection object 10 is classified into a non-defective product and a defective product.

  The camera 2 is a CCD camera, for example, and is installed so that the optical axis is perpendicular to the inspection surface of the inspection object 10, and images the inspection surface from directly above. A video signal including the inspection surface of the inspection object 10 captured by the camera 2 is output to the image processing apparatus 1 via the connection cable 4. Further, in the vicinity of the camera 2, a light 3 for irradiating light for illumination on the inspection surface of the inspection object 10 from an obliquely upward direction is installed, and the camera 2 has defects such as dust and scratches existing on the inspection surface. Is set so as to be easily imaged.

  The image processing apparatus 1 includes, for example, a monitor 1a formed of a liquid crystal display, an apparatus main body 1b connected to an equipment control apparatus (not shown) that controls a production line of the inspection object 10, and a keyboard connected to the apparatus main body 1b. 1c and mouse 1d. The image processing apparatus 1 is connected to, for example, a commercial power source (not shown), and operates with power supplied from the commercial power source as operating power.

  The apparatus main body 1b includes a capture board that converts a video signal captured by a camera into image data, a CPU (Central Processing Unit) that performs image quality calculation, RAM (Random Access Memory), image data, and pass / fail. A hard disk drive (HDD) that stores the determination result and a power supply unit that is connected to a commercial power supply and supplies operating power are combined.

  Further, the apparatus main body 1b is used for determining pass / fail according to a reference image (see FIG. 2A) in which no defect exists on the inspection surface of the inspection object 10, the number of defective pixels, and the position of the defective pixels. A plurality of inspection conditions C1... Cn are set in advance. The appearance inspection apparatus uses the inspection condition C1 as a main inspection condition to determine and classify non-defective / defective products according to the result of the quality determination based on the inspection condition C1, and the quality determination based on the inspection conditions C2 ... Cn. The determination result is used as reference information when the user later changes the inspection condition.

  When the keyboard 1c and the mouse 1d are operated by the user, the operation signal is output to the apparatus main body 1b, and various information such as the occurrence frequency held by the apparatus main body 1b and the setting of the inspection conditions C1... Cn are changed. The

  Here, a method and a procedure for determining pass / fail of the inspection object 10 will be described.

  First, the video signal input from the camera 2 is converted into image data composed of a plurality of pixels based on the resolution of the camera 2 and the capture board by the capture board of the apparatus main body 1b. Next, differential processing is performed on the image data, for example, to generate a differential image, and edge detection is performed by performing a non-linear calculation centering on a pixel having a large differential value of the differential image. After that, based on the detected edge information, the position of the reference image and the direction of the video are matched, and the reference image is subtracted from the image data. If the pixel after the subtraction is not within the predetermined range, the defective pixel Detect as. The position information of the detected defective pixels is stored in the HDD of the apparatus main body 1b by the apparatus main body 1b together with the video image of the inspection object 10.

  Next, the position and number of the detected defective pixels are compared with the inspection condition C1, and the quality of the inspection object 10 is determined. For example, if the number of defective pixels is less than 20 pixels, it is determined as a non-defective product, and if the number of defective pixels is 20 pixels or more, the device main body 1b outputs a determination result of pass / fail determination to the equipment control device, and equipment control Each production apparatus is controlled so that the apparatus can sort non-defective products and defective products based on the determination result. At the same time, the position and number of detected defective pixels are compared with the inspection conditions C2. The determination results based on these inspection conditions C1 to Cn are stored in the HDD of the apparatus main body 1b together with the position information of the defective pixels and the video of the inspection object 10 described above.

  In this way, the image processing apparatus 1 performs pass / fail determination for all the inspection objects 10 flowing on the production line, and the facility control apparatus controls each production apparatus according to the determination result of pass / fail determination, We sort good and defective products.

  Next, display contents displayed on the monitor 1a will be described. The display contents of the monitor 1a are switched when the user operates either the keyboard 1c or the mouse 1d, and first to third display contents to be described later are displayed. First, as the first display content, at least one of shading or hue of each pixel is changed according to the appearance frequency calculated from the position information of the defective pixel stored in the HDD of the apparatus main body 1b in the above-described pass / fail determination. And superimposed on the image of the inspection object 10 (see FIGS. 2B to 2F). 2B is a display example when there is a scratch (scratch 11), and FIG. 2C is a display example when a suction pad trace (suction pad trace 12) remains. FIG. 2D shows a display example when dust (dust 13) is attached. Further, FIG. 2E is a display example when the marks and dust of the suction pad are combined, and FIG. 2F is a display example when scratches and dust are combined.

  Here, as a method of calculating the appearance frequency, for example, the entire image is divided into pixel areas of 4 × 4 pixels, and when even one defective pixel exists in each pixel area, the occurrence frequency is added to determine the occurrence frequency. calculate. The calculated occurrence frequency is compared with the occurrence frequency value designated by the user using the keyboard 1c, and the pixels in the pixel area equal to the designated occurrence frequency are displayed in a semi-transparent red color, for example. By doing so, it is possible to prevent the display of defects with a low frequency of occurrence, for example, caused by dust adhering.

  Note that the image of the inspection object 10 to be displayed may be a reference image used for the quality determination, or may be an image of the inspection object 10 stored in the HDD for the quality determination. In addition, the occurrence frequency designated by the user can be displayed only in a pixel region where the occurrence frequency is within a specific range by setting at least one of an upper limit and a lower limit.

  As a second display content, a pixel area in which the number of consecutive occurrences of defects in the same pixel area matches the number of consecutive occurrences designated by the user using the keyboard 1c is changed in at least one of lightness and shade of pixels. Thus, the image of the inspection object 10 is displayed in an overlapping manner. More specifically, when the user sets “8” as the continuous number, the positions of the defective pixels of the inspection object that have been continuously determined to pass or fail are respectively scanned, and the inspection includes defective pixels in the same pixel region. When eight objects 10 are continuous, the corresponding pixel region is displayed with the pixel shade and hue changed. Note that a method similar to the method in the first display content is used for the generation frequency calculation method and the pixel shading and hue change method.

  As the third display content, an image of the inspection object 10 including the defective pixels having the appearance frequency calculated from the position information of the defective pixels stored in the HDD of the apparatus main body 1b in the above-described pass / fail determination is displayed. To do. Note that the calculation method of the occurrence frequency uses the same method as the method in the first and second display contents.

  In this way, the exact position and frequency of defects can be communicated to the user in an easy-to-understand manner, the cause can be quickly identified and production lines can be adjusted and inspection conditions can be changed at an early stage. .

  Note that the first to third display contents may be displayed in such a manner that the frequency of occurrence of defects is superimposed on the image of the inspection object 10 when the quality determination based on the inspection conditions C1 to Cn is different. . By doing in this way, a new inspection condition can be selected and a setting can be changed on the basis of inspection conditions C1-Cn.

1 Image processing device 1a Monitor (display unit)
1b Device body (defect location detection unit, storage unit, calculation unit)
1c keyboard 1d mouse 2 camera (imaging means)
3 Lamp 4 Connection cable 10 Object to be inspected

Claims (4)

An imaging means for imaging an inspection object;
Using the image data obtained by imaging the inspection object by the imaging means, a defect location detector that detects the number and position of defective pixels present in the object;
A storage unit for storing the number and position of defective pixels detected by the defective part detection unit;
A calculation unit that calculates the occurrence frequency of defects for each pixel region including a predetermined number of pixels based on the number and position of defective pixels in a plurality of inspection objects stored in the storage unit;
Display means for displaying a pixel region having a specified occurrence frequency based on a calculation result of the calculation unit, by changing at least one of the shading and the hue of the pixel and superimposing the image on the image of the inspection object. Feature visual inspection device.   The display unit superimposes a pixel region in which the number of consecutive defects in the same pixel region matches the designated number of consecutive occurrences on the image of the inspection object by changing at least one of pixel shading and hue. The visual inspection device according to claim 1, wherein the visual inspection device is displayed.   A plurality of inspection conditions relating to the number and position of defective portions are set, and an inspection unit that determines the quality of an inspection object based on each inspection condition is provided, and the display unit determines the result of the quality determination based on the plurality of inspection conditions 3. The appearance inspection apparatus according to claim 1, wherein the frequency of occurrence of defects is displayed so as to be superimposed on the image of the inspection object.   The display unit displays image data including a pixel region whose occurrence frequency calculated based on the number and position of defective pixels in a plurality of inspection objects stored in the storage unit is a predetermined frequency or more. The appearance inspection apparatus according to any one of claims 1 to 3.

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