KR20170107952A - Optical appearance inspection device and optical appearance inspection system using same - Google Patents

Abstract

There is provided an optical visual inspection apparatus capable of reducing the number of cameras used and miniaturizing the apparatus itself and requiring no operation time such as moving the camera and performing various types of inspection in a short time, Inspection system. And processing means for analyzing and judging whether or not an apparent defect exists in the inspection object by using the photographed image photographed by the photographing means, An optical appearance inspection for analyzing changes in color and / or brightness of image data on a plurality of lines respectively selected in the regions where the intensity of the light irradiated to the inspection target is different while acquiring and judging whether or not each inspection defect exists in the inspection object Device.

Description

Technical Field [0001] The present invention relates to an optical appearance inspection apparatus and an optical appearance inspection system using the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical visual inspection apparatus for inspecting the appearance of various articles such as foods and industrial products, and a photographing means which can be suitably used therefor. In particular, the present invention relates to an optical visual inspection apparatus for analyzing image data obtained by photographing an article to check the presence or absence of irregularities such as scratches, burrs, deformation, or the like on the surface of the article, To a photographing means.

(Conveyed) by a conveyor belt or the like to inspect defects on the surface of various articles (hereinafter also referred to as " object to be inspected ") such as food products such as crops and processed foods, industrial products such as resin molded articles, The article is photographed, and the photographed image data is analyzed.

The applicant of the present application has also proposed an apparatus for inspecting foreign substances or the like using such image data in Patent Document 1 (Japanese Patent Application Laid-Open No. 2010-8339). In this document, in order to easily and surely inspect foreign substances in a powder filled in a transparent container, the transparent container is subjected to oscillation in which a reciprocating oscillation in the longitudinal direction and a reciprocating oscillation in the transverse direction are applied to the transparent container to circulate the powder in the transparent container, A method for inspecting a foreign matter in a powder in a transparent container that images a flowing powder and checks presence or absence of a foreign substance using the obtained image.

In addition, in order to inspect the appearance of defects in the past, it is necessary to check the inspection contents (that is, the inspection of the attachment of the garbage, the inspection of the presence or absence of scratches and burrs on the surface, I had to change the direction of shooting or the way of light contact. For example, in the inspection of the garbage adhered to the object to be inspected, it is necessary to inspect the object immediately from the oblique direction. For this reason, when various surface tests are performed on the object to be inspected, the object to be inspected must be reciprocated several times or a plurality of inspection stations must be installed and inspected.

At this time, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-333449), in order to shorten the inspection time, a backlight panel inspection apparatus capable of carrying out a performance inspection by only once reciprocating has been proposed. That is, in this document, an inspection apparatus for inspecting a plate-like inspection object placed in an inspection region, a placement table on which the inspection object is removably mounted, a placement means for moving the placement table in a horizontal direction, A camera for photographing at a position directly above the mount table, two cameras for photographing the mount from right and left sides of an oblique upper surface, and a camera for detecting a defect based on the image from the camera And a display unit for displaying a detection result of the detection unit. The examination of the subject is completed only by reciprocating the subject one time by the camera.

In addition, a technique for automating the change of the angle of inspection (photographing) according to the types of defects to be inspected has been conventionally proposed. For example, Patent Document 3 (Japanese Patent Laid-Open Publication No. 2006-300913) proposes a method of automatically moving a camera imaging angle in a forward path and a return path to change the angle of a positional relationship between a camera and a work, A technique for facilitating the inspection according to the present invention has been proposed. That is, this document proposes a light guide plate inspection apparatus having a rotary actuator and a brake for holding a multiple line sensor camera for inspecting a light guide plate on a light guide plate loading stage and changing the shooting angle of the camera for each structure.

Also, conventionally, a photographing apparatus provided with a line sensor camera which has been studied so that an object to be photographed having irregularities on the surface can be clearly photographed has been proposed. For example, Patent Document 4 (Japanese Patent Application Laid-Open No. 2011-223233) discloses an image pickup apparatus comprising an objective lens and a line scan sensor arranged in the imaging depth of the objective lens and composed of a plurality of image pickup elements, And the plurality of line scan sensors include a line sensor camera in which imaging positions of the line sensors are different from each other, image reading means for sequentially reading the imaging results of the plurality of sets of line scan sensors, Out-of-focus-image extracting means for extracting an in-focus (an in-focus, focused object at the time of photographing with a camera) out of a plurality of read out unit-taken images, and a in-focus shot image generating means for combining the extracted in- There is proposed an image pickup apparatus equipped with the above-

Japanese Patent Application Laid-Open No. 2010-8339 Japanese Patent Application Laid-Open No. 2007-333449 Japanese Patent Application Laid-Open No. 2006-300913 Japanese Patent Laid-Open Publication No. 2011-223233

As described above, in the case of inspecting defects appearing on the surface of an article (inspection object), it is necessary to inspect whether or not the surface of the article is attached with garbage, or to check the irregularities such as scratches, burrs, I had to change the direction of shooting the subject or the way the light came in contact. For example, when the inspection target is a light guide plate and the appearance inspection in the manufacturing process is automated, it is necessary to photograph the transmission light to inspect the discolored defects such as presence or non-existence of carbonized foreign matters in the resin In order to inspect gentle uneven defects caused by the melting temperature and the injection pressure at the time of resin molding, it is necessary to take a picture by irradiating scattering light, and to take a picture of a wound caused by a mold or an extractor · In order to inspect rugged irregularities such as burrs, we had to shoot low angle lighting. Therefore, it was necessary to prepare a lighting condition adapted to the characteristic of the defect to be inspected and a camera for photographing under each lighting condition.

Therefore, in order to solve this problem, it has been proposed in the past to install a plurality of cameras as described in Patent Document 1, or automatically correct the direction of the camera as disclosed in Patent Document 2.

However, when a plurality of cameras are used, there is a problem that the number of cameras installed increases and the cost is increased, and the installation space of the camera is further secured. In addition, when the direction of the camera is automatically corrected, an operation time for moving the camera to a predetermined position is required, thereby increasing the inspection time.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an optical visual inspection apparatus that reduces the number of cameras to be used and the number of cameras installed, thereby miniaturizing the apparatus itself, and an optical visual inspection system using the same. It is an object of the present invention to provide an optical visual inspection apparatus capable of performing various types of inspection in a short time without requiring an operation time such as moving a camera while reducing the number of cameras used and an optical visual inspection system using the same. We will do it.

Further, the object to be inspected is conveyed by a conveying means such as a conveyor belt, and the size, height or thickness of the object to be inspected varies. That is, the object to be inspected may also be a three-dimensional shaped article such as a box-shaped box or a tubular shape with a height, or may be a plate-shaped or sheet-shaped article having a low height. Therefore, in order to photograph an article having a different height or thickness from a proper angle, it is necessary to adjust the installation position and angle of the camera or the installation position and angle of the inspection object every time the inspection is performed, so that the operation has been troublesome.

At this time, even when inspecting an object to be inspected having different sizes, heights, or thicknesses, the present invention can be applied to an optical inspection system that can inspect the appearance of an object to be inspected without changing the height or angle of the camera, illumination, A third aspect of the present invention is to provide an appearance inspection apparatus and an optical appearance inspection system using the same.

In addition, in the past, there has been a problem that the presence of carbonized foreign substances in the resin as a raw material for production, discolored defects such as unhardened solution, melting temperature during resin molding, gentle uneven defects caused by injection pressure, In the case of inspecting defects appearing on the appearance of the inspection object such as rugged irregularities such as scratches or burrs caused by defects, it is necessary to shoot images for inspection for each defect.

Therefore, it is an object of the present invention to provide an optical visual inspection apparatus capable of inspecting various kinds of defects appearing in the appearance of an inspection object as described above by one shot, and an optical visual inspection system using the same. We will do it.

Further, when the surface inspection is performed on the basis of the photographed image, the transmission position and the reflection position of the irradiated light may vary due to the change of the thickness or height position of the inspection object. At this time, it is desirable to eliminate such fluctuations, and it is preferable that the " change of irradiated light " caused by defects on the surface is desirably acquired as data.

In this respect, in Patent Document 4, it is disclosed that an entire surface of an object to be photographed having irregularities on the surface is clearly photographed by extracting and synthesizing focused photographic data. However, the invention relating to this document is intended to clearly photograph an object to be photographed having irregularities on its surface, and a plurality of sets of line scan sensors are arranged so that their imaging positions are different from each other. Therefore, in this technique, it is possible to acquire the photographed image of the optimum focal length, but it is not possible to acquire the photographed image for the surface inspection involving the positional relationship with the light source. The technology of Patent Document 4 is described in claim 4 that each of the line scan sensors is composed of a plurality of sensor arrays read in the TDI system and that the sensor array has 256 lines in general In this technique, the height resolving ability is limited by the inclination angles and the number of lines of a plurality of image pickup devices, and it is considered that the degree of freedom of follow-up in practical use is low.

Therefore, according to the present invention, an optical appearance inspection capable of inspecting the surface of an object to be inspected at high speed and / or with high accuracy by using the photographing means studied so as to obtain an optimum image for surface inspection while securing a wide field of view Apparatus, and an optical appearance inspection system using the same.

In order to solve at least one of the above problems, according to the present invention, by analyzing and judging image data on a plurality of lines selected in the inside and outside of the area irradiated by the illuminating means, the various defects appearing in the appearance of the inspected object And to provide an optical appearance inspection system using the same.

That is, the optical visual inspection system according to the present invention comprises imaging means for imaging an object to be inspected, and processing means for analyzing and determining whether or not the object to be inspected is defective, using the captured image taken by the imaging means And the processing means analyzes the change in color and / or brightness with respect to the image data on a plurality of lines each of which is selected in the region where the intensity of the light irradiated to the object to be inspected is different while acquiring the photographed image from the photographing means, It is judged whether or not each of the defects is apparent.

&Quot; As for the photographing means &

In the optical visual inspection apparatus according to the present invention, the photographing means photographs an object to be inspected and obtains a photographed image, and is composed of (including?) Various kinds of imaging elements. Particularly, it is preferable that the photographing means is capable of acquiring the photographed image data as electronic data. This is for smoothly performing the image analysis processing in the processing means. Such an imaging device may be a CMOS image sensor or a CCD image sensor. Particularly, it is preferable that the camera is capable of taking an image at any arbitrary line like a CMOS image sensor camera. A camera capable of photographing such arbitrary lines can be constituted by including a photodiode column in which a plurality of photodiodes are arranged in a line. By providing a plurality of photodiode columns, the processing means acquires image data in a plurality of lines . On the other hand, in the case of a camera that acquires a planar photographed image such as a CCD image sensor, it is possible to extract an image on a plurality of lines from a photographed image on the surface of the object to be inspected, and obtain image data to be analyzed.

Particularly, as this photographing means, it is preferable to use a camera which has an image pickup element on a surface in which a plurality of photodiodes are arranged in the vertical and horizontal directions, and can extract an arbitrary plurality of lines in the image pickup field of view. This is because an image similar to the case of using a plurality of photographing means and illumination means can be obtained simply by passing through the photographing region without stopping the inspection object by picking up an image on a line arbitrarily selected from the planar imaging elements. This is because it is unnecessary to extract a necessary line (area) after acquiring a photographed image such as a camera using an image sensor that captures a planar image, thereby increasing the processing speed. That is, by using the photographing means using the CMOS image sensor, the inspection process can be simplified, the amount of data can be reduced, and the inspection time can be shortened.

It is preferable that the photographing means is configured so as to be able to acquire optimum image data even if the transmission position or the reflection position of the light irradiated by the difference or change in the material of the object to be inspected, Do. In order to do this, for example, an inspection object is photographed in a region having a constant width in the scanning direction, an area in which a change in color and / or brightness is optimal from the captured image is extracted and combined, .

That is, the photographing means includes a photographing section for photographing in a plurality of lines arranged in parallel in the scanning direction of the object to be inspected, and a plurality of lines for photographing the photographing section in a direction perpendicular to the scanning direction Direction), extracting a region of a specific line based on the comparison, and combining the combined image data with one or more lines of image data

In the optical visual inspection apparatus using such a photographing means, the photographing section photographs a plurality of lines arranged in parallel in the scanning direction of the inspected object, on each of a plurality of lines respectively selected from the regions of different intensity of light irradiated to the inspected object , And an optical visual inspection apparatus using a plurality of image data of one line or a plurality of lines synthesized by the image processing section as image data on a plurality of lines analyzed by the processing means. In the optical visual inspection apparatus thus structured, the color and / or the intensity of the specific region of the plurality of lines arranged in the scanning direction of the object to be inspected is used as the image data (that is, the image data acquired in each region having the different intensity of the irradiated light) It is possible to perform surface inspection more reliably and precisely by using image data of one or a plurality of lines which are obtained by comparing the brightness of the image and then combining and combining the area images which are optimal for each surface inspection. In the case where a plurality of lines arranged in the scanning direction of the inspection object are used as the imaging area of the inspection object to be imaged at one time, the inspection object is transferred in units of a plurality of lines arranged in the scanning direction of the inspection object And thus the inspection speed may be improved.

<< About Processing Means >>

&Lt; Configuration of processing means >

The processing means analyzes the change in color and / or brightness with respect to the image data on a plurality of lines each of which is selected in the region where the intensity of the light irradiated to the object to be inspected is different while acquiring the taken image taken by the photographing means, It is a device for judging the presence or absence of each appearance defect. The image data interpreted by the processing means may be an image obtained by processing the photographed image in addition to directly using the photographed image according to the photographing means. That is, the processing means is a processing means that acquires a captured image from the image capturing means, converts the captured image into an image data to be analyzed, or changes the color and / or brightness of the image data created by performing image processing on the captured image And the appearance defect in the inspection object may be inspected. Therefore, this processing means is constituted by a CPU (Central Processing Unit) or a memory for performing numerical calculation, information processing, device control and the like necessary for the analysis and judgment, do. The image processing for the photographed image includes a process of extracting an arbitrary region from the photographed image, a combining process of the photographed image, and a process of correcting brightness, saturation, contrast, and the like.

The processing means interprets a plurality of lines of image data. The image data of a plurality of lines are subjected to image processing in addition to image data of a plurality of lines obtained by photographing with a camera using an image sensor capable of photographing in a plurality of arbitrary lines as in the case of a CMOS image sensor, It may be image data of a plurality of lines obtained by cutting out and extracting from a plane image photographed by a camera using a sensor. Particularly, in the case where the processing means acquires an image photographed in a plane, extraction processing in an image on a ghost plane can be executed by the processing means.

&Lt; Regarding the image data of the line acquired by the processing means >

The image data of a plurality of lines analyzed by the processing means is image data of a plurality of lines each of which is selected in an area where the intensity of the light irradiated to the inspection object is different. The &quot; light irradiated to the object to be inspected &quot; refers to light reflected from the object to be inspected or light transmitted through the object to be inspected, and the image data of the plurality of lines are respectively selected in regions where the intensity of the reflected light or the transmitted light is different. The intensity of the light irradiated to the object to be inspected can be measured also by the light (light irradiating the object to be inspected) directed toward the object to be inspected, and it is possible to measure the luminance of the object irradiated with the light, It can be specified by measuring the reflected light of the object or the luminance of the transmitted light.

The light irradiated to the object to be inspected may be natural light in addition to the light irradiated by the illuminating means provided with the light source. This is because, if the direction of irradiation with respect to the object to be inspected is specified even in natural light, it is considered that the kind of the apparent defect appearing in the image differs depending on whether the line-shaped image data is acquired at which position. However, the optical visual inspection apparatus according to the present invention preferably further includes an illumination means for scanning light to the object to be inspected in order to keep the irradiation conditions such as the light irradiation position and the luminance constant. At this time, it is preferable that image data of a plurality of lines analyzed by the processing means are respectively selected in regions where the intensity of the light irradiated by the illuminating means is different.

The illuminating means can use various illuminations for illuminating the object to be inspected. The light irradiated by the illuminating means may be invisible light such as infrared light, ultraviolet light and X-ray in addition to visible light. In particular, in the case of an illumination means for irradiating visible light, light having a peak at a specific wavelength region such as blue, green, red, or yellow may be irradiated in addition to white light. Therefore, the photographing means is not limited to photographing the light in the visible light region but also includes the means capable of photographing light in the invisible light region. In view of the fact that the processing means interprets the image data of a plurality of lines, it is preferable that the lighting means is a line illumination which irradiates light in a long range. When line illumination is used as the illumination means, it is preferable that the extending direction of the illumination and the extending direction of the image data of a plurality of lines used for the analysis are parallel to each other, In the direction perpendicular to the scanning direction of the recording medium.

The light taken by the photographing means may be light (transmitted light) transmitted through the object to be inspected, or light (reflected light) reflected from the object to be inspected. Therefore, the object to be irradiated with light may be transparent or opaque, and some transparent or partially opaque articles may be used. When taking an object to be inspected, in general, when the object to be inspected is transparent, it is preferable to photograph the object to be inspected and to observe the appearance of the defect. However, if the transparent object to be inspected generates reflected light, the reflected light may be photographed to examine the apparent defect. On the other hand, when the object to be inspected is opaque, only the reflected light of the irradiated light is photographed on the object to be inspected to check the appearance of the defect.

As described above, in the case where the optical visual inspection apparatus according to the present invention includes the illumination means, the image data of a plurality of lines to be analyzed by the processing means is preferably selected in a region where the intensity of the light irradiated by the illumination means is different Do. That is, it is preferable that the light intensity is selected in each region of the region where the light intensity is different, such as at least the region where the illumination means irradiates light and the region where the illumination means irradiates the light. This is because the types of defects that can be observed (or are easy to observe) are different depending on whether the illuminating means is the inside or outside of the region irradiating the light. Therefore, it is possible to obtain image data that is easy to observe in response to various types of defects by acquiring image data for analysis from the inside and outside of the irradiated area in the illuminating device.

The "image data in a plurality of lines" interpreted by the processing means may include, in addition to the region irradiated with light by the irradiating means, the region irradiated with the light by the irradiating means, It is preferable to select at least two of the three areas.

That is, the optical visual inspection apparatus according to the present invention further includes an illumination means for irradiating light to the object to be inspected, and the image data on a plurality of lines analyzed by the processing means is irradiated with light by the illumination means At least two or more of the irradiation central region which is the central portion of the region, the outline region of the region irradiated with the light by the illumination means, and the non-irradiation region which is not irradiated with light by the illumination means as the vicinity of the outline region As shown in FIG. It is particularly preferable that the image data of the plurality of lines is selected in each of the irradiation center region, the contour region, and the non-irradiation region.

As described above, the region for acquiring the image data to be analyzed is specified as the irradiation central region, the outline region, and the non-irradiation region, and the region for acquiring the image data to be analyzed is specified in relation to the irradiation region of the illumination means . Therefore, if the irradiation region in the illumination means can be specified, the position of the image data of the line analyzed by the processing means can be specified. In the case where a plurality of inspection objects having the same shape and size are to be inspected for the first time, if the irradiation area of the illumination means is specified for the first time, A plurality of inspection objects can be inspected continuously by using the image data of the position (line) of the inspection object. Therefore, in this case, it is preferable to identify the line (s) at which the image data to be analyzed is obtained after confirming which line is the object to be actually inspected at first and which line should be used to obtain the image data to be analyzed . Particularly, in the case of setting which line of image data is to be analyzed in the outline area and the non-irradiation area, defects (irregularities such as scratches, burrs, distortion, adhesion of foreign matter, It is preferable to actually measure and specify a position at which a defect such as a color defect in the image is likely to appear. When the image pickup means is a camera using an image sensor such as a CMOS image sensor capable of taking an image on a plurality of arbitrary lines, it is preferable to acquire the image data on the set lines.

The optical visual inspection apparatus according to the present invention further includes an illumination means for irradiating light to the object to be inspected and the image data on a plurality of lines analyzed by the processing means includes It is also preferable to select to be selected in at least any two or more regions of the highest high luminance region, the luminance change region in which the luminance changes sharply, and the low luminance stable region in which the change is stable at a lower luminance than the luminance change position Do. It is particularly preferable that the image data of the plurality of lines is selected in each of the high luminance region, the luminance change region and the low luminance stable region.

As described above, by obtaining the image data to be analyzed as the high luminance area, the luminance change area, and the low luminance stable area, the brightness of the actually illuminated light is measured and the image data to be analyzed is acquired based on the measured data The area can be specified. In the case of inspecting a plurality of objects to be inspected having the same shape and size, it is preferable to first measure the irradiation luminance and specify the line position of the image data to be analyzed , And thereafter, by using image data at a predetermined position (line), a plurality of inspected objects can be continuously inspected for appearance. Also in this case, it is desirable to identify the line (s) at which the image data to be analyzed is acquired after confirming which line in the object to be actually inspected is preferable to acquire the image data to be analyzed. Particularly, in the case of setting which line image data is to be analyzed in the luminance change area and the low brightness stability area, defects (defects such as scratches, burrs, distortions, irregularities, Defects such as color defects such as nonuniformity) are preferably measured and specified. When the image pickup means is a camera using an image sensor such as a CMOS image sensor capable of taking an image on a plurality of arbitrary lines, it is preferable to acquire the image data on the set lines.

<Regarding Processing and Inspection of Image Data in Processing Unit>

The processing means may be configured to perform the processing in the following manner in the "regions having different light intensities," "irradiated central regions, outline regions, and non-irradiated regions", or "high brightness regions, It is possible to obtain image data on a plurality of lines, analyze and judge them by performing image processing as required, thereby making it possible to detect defects such as foreign matter adhering to the inspection object and discoloration appearing on the appearance of the inspection object, Defects, and rugged irregularities such as scratches and burrs. At this time, the image data in a plurality of lines selected in each area may have different widths in each line, and any or all of the line widths of image data in a plurality of lines may be arbitrarily adjusted.

In other words, the processing means acquires image data on a plurality of lines to be analyzed on the captured image taken by the photographing means. As the image data, when the image pickup means is a camera using an image sensor capable of photographing in a plurality of arbitrary lines such as a CMOS image sensor, by scanning the photographing means, a plurality of lines (A line-shaped image extending in the direction intersecting the scanning direction), and developing it as a surface image of the entire inspection object by combining it in the scanning direction for each line can be used have. The process of developing such line-shaped image into a face image may be performed by photographing means or processing means.

On the other hand, when the photographing means is a camera using an image sensor for photographing a planar image such as a CCD image sensor, the photographed image acquired by the photographing means becomes a planar image. At this time, the processing means selects and extracts the predetermined region as the line-shaped image in each of the plurality of captured images acquired by scanning the photographing means, Image, and this can be used as plane image data to be analyzed. In this case, however, it is required to extract a plurality of areas, which are arbitrarily specified in relation to the area irradiated with light from the image obtained by one shot, into the illumination means in the form of a line.

The processing means can analyze the change in color and / or brightness in the image data acquired by the above-described processing to determine the presence or absence of each apparent defect in the inspection object. The analysis of the change in color and / or brightness with respect to the image data can be determined by determining the color or brightness of each pixel and obtaining the amount of change from the surrounding pixels.

The kinds of defects that can be inspected here include all defects that can be observed from the appearance. That is, as far as foreign matter, discoloration, and irregularities on the surface of the object to be inspected are permeated beyond the defects, it is possible to inspect foreign matter and discoloration of defects existing in the object to be inspected. Therefore, there are problems such as carbonized foreign matters of the resin as a raw material for production, discolored defects such as unhardened solution, melting temperature during resin molding, gentle uneven defects caused by injection pressure, The defects appearing on the appearance of the object to be inspected such as a rugged irregular defect of the inspection object can be inspected.

&Lt; Preferred Embodiment &gt;

As described above, when a line-shaped image acquired for each of a plurality of lines is developed as a plane image for each line as image data and a defect in the appearance of the inspection object is inspected based on the image data, It is preferable that the scanning for photographing by the means is completed at a time in order to shorten the inspection time. In the present invention, image data of another position (line) can be acquired in relation to the region irradiated with the light by the illumination means only by scanning the imaging means once, and it is possible to obtain various kinds of apparent defects Can be inspected.

In addition, in the optical visual inspection apparatus according to the present invention, it is preferable that there is only one photographing means as a constituent element in order to simplify the structure of the apparatus itself and downsize it. That is, it is preferable to acquire image data on a plurality of lines from a captured image by one imaging means. However, two or more photographing means may be used. In the case of using two or more photographing means, the area to be photographed by each photographing means can be different. Specifically, when the length in the direction perpendicular to the scanning direction of the photographing means (length in the width direction of the photographing area) is long, a plurality of photographing means can be arranged in the longitudinal direction. In this case, the area to be photographed by each photographing means is different in the longitudinal direction of the object to be inspected. It is also possible to photograph some of the image data on a plurality of lines required for inspection by some photographing means and take image data on other lines with another photographing means.

Further, in the present embodiment, it is preferable that the photographing means is configured to combine optimal image data for each region in which the intensity of light irradiated to the object to be inspected is different. The photographing means is a photographing means provided with an optical element in which a plurality of photodiode rows constituted by a plurality of photodiodes are arranged in parallel in parallel. The photographing means photographs the photodiodes so as to realize photographing in a plurality of port diode rows at arbitrary two or more locations. Means, that is, a photographing means in which ROI (Reagent Of Interest) is set at two or more, preferably three, of the photographing area.

Therefore, this photographing means is an image taking means used in an optical visual inspection apparatus for judging whether or not an apparent defect exists in an image of an inspection object while scanning, and includes a photographing section for photographing on a plurality of lines arranged in the scanning direction of the inspection object, The color and / or brightness of each of the plurality of lines photographed by the photographing section are compared for each region in the direction orthogonal to the scanning direction, and then the region of the specific line is extracted based on the comparison and the image data of one line It is possible to provide a photographing means for an optical visual inspection apparatus comprising an image processing section for synthesizing.

The imaging unit in the imaging unit can be configured by using an imaging device such as a CMOS image sensor or a CCD image sensor and can be configured with an optical part such as a lens for focusing and imaging incident light from the object to be inspected . Regarding such an image pickup device, in the case of a CMOS image sensor, since an image is obtained for each row of photodiodes, comparison processing of color and / or brightness for each region aligned in the direction orthogonal to the scanning direction can be performed at high speed. On the other hand, in the case of using a CMOS image sensor, it is necessary to perform a process of cutting out image data for each area arranged in a direction orthogonal to the scanning direction from the photographed image data.

The image processing unit in the photographing unit may be configured using a processing unit that performs image processing. The processing apparatus may be provided in a housing such as the imaging unit, or may be provided in a housing or apparatus different from the photographing apparatus, and may be configured to process the image acquired by the imaging unit. In other words, such a photographing means may be embodied as a module in which the image pickup section and the image processing section are integrated, and they may be separately provided to realize interlinking processing. Therefore, a digital camera may be used as the image pickup section, and a computer may be used as the image processing section.

In the above photographing means, a plurality of rows of photodiodes arranged in the direction crossing the scanning direction are provided adjacent to each other in the scanning direction, and the brightness of the photodiodes arranged in the scanning direction in the plurality of photodiode rows acquired by one imaging And / or a color of an arbitrary photodiode can be extracted or calculated under conditions preliminarily set by comparing them. Then, by combining the extracted or computed images, it is possible to synthesize one line of image data with respect to the photographing position. Thus, by generating image data of one line to be used for inspection, the inspection accuracy can be improved and the inspection speed can be increased by reducing the amount of data.

In addition, as conditions under which the image (pixel-by-pixel image) of the photodiodes arranged in the scanning direction is extracted or calculated, the "no processing mode", the "maximum luminance mode", the "minimum luminance mode" &Quot;, &quot; intermediate brightness mode &quot;, and the like.

The &quot; no processing mode &quot; is a mode for directly acquiring pixels aligned in the scanning direction and can be acquired as a monochrome image.

The &quot; maximum luminance mode &quot; is a mode for extracting pixels whose luminance is the maximum in the pixels arranged in the scanning direction in the pixel columns arranged side by side in the direction crossing the scanning direction and acquiring image data synthesized by one line to be. In this mode, image data of one line to be used for inspection can be generated with the highest luminance value targeted for false defect.

The &quot; minimum luminance mode &quot; is a mode for extracting pixels having the minimum luminance in the pixels arranged in the scanning direction and obtaining image data obtained by synthesizing the pixels with one line. In this mode, one line of image data to be used for inspection can be generated with a minimum luminance value targeted for a dark defect.

The &quot; average luminance mode &quot; is a mode for calculating the average value of the luminance of the pixels arranged in the scanning direction among the pixel columns arranged in the direction crossing the scanning direction, and acquiring the image data obtained by synthesizing the average values of the luminance in one line. In this mode, the average of the luminance in each pixel is calculated, and it is possible to acquire a processed image as if it is through the soft filter as inspection image data.

The &quot; intermediate luminance mode &quot; is a mode for extracting pixels whose luminance is intermediate in the pixels arranged in the scanning direction, and acquiring image data obtained by synthesizing the pixels in one line. In this mode, since pixels having an average brightness are acquired, image data from which spike noise is removed can be obtained. In particular, in the &quot; average luminance mode &quot;, clear image data can be obtained even when the image is blurred.

It is preferable that the photographing means is formed so as to be able to set the above mode for each region (i.e., a &quot; partial scan region &quot;) in which the intensity of light irradiated to the object to be inspected is different. This is to obtain image data necessary for inspection in each partial scan region more clearly. It is also preferable that the photographing means includes an image adjusting means for making the offset value and / or the gain value different for each partial scan region. In the region where the intensity of the light irradiated to the object to be inspected is different, there is provided an image adjusting means for varying the offset value and / or the gain value for each region, in which brightness required for photographing is different depending on the type of defect appearing on the surface of the object to be inspected The optimum image data required in each area can be obtained. By adjusting the digital gain or the offset, an optimum image can be obtained in accordance with the color or transmittance of the object to be inspected or the intensity (luminance) of the light to be irradiated.

«About optical visual inspection system»

Further, in the optical visual inspection apparatus according to the present invention, an optical visual inspection system can be provided by further carrying a configuration for transporting the object to be inspected. That is, the optical visual inspection system configured by using the optical visual inspection apparatus according to the present invention is characterized by comprising: inspection object moving means for placing and transporting an inspection object; It is possible to provide the optical appearance inspection system configured to acquire the photographed image acquired by the processing means in association with the photographed position calculated on the basis of the moving speed or the movement amount acquired by the transfer detection means .

Examples of such inspection target conveying means include a conveyor and a manifold. Examples of the conveyance detecting means include a rotary encoder and a linear encoder. The photographing means constituting the optical visual inspection apparatus photographs an image of each line in the photographed image (line-shaped image) by photographing an image at a timing at which a signal attributed to the moving speed or movement distance acquired by the conveyance detection means is acquired And may be associated with the photographing position. As a result, it is possible to correct the position at the time of developing a plane image in a plurality of acquired line-shaped images while suppressing unevenness of the imaging resolution ability due to the variation of the moving speed of the inspection object in the inspection object moving means.

In the optical visual inspection system, the inspection object moving means may include a holding means for sucking the inspection object to be transported in a mounted state or for tightly mounting the inspection object. In order to maintain a constant distance from the photographing means when the object to be inspected is a plate or sheet shape. Such a holding means may be constituted such that a downflow air is blown against an object to be inspected and the object to be inspected is stuck to the means for moving the object to be inspected or a structure in which a fine opening is provided on the surface of the object to be inspected, And the aspiration surface of the object to be inspected is sucked from the opening. It is sufficient that such a maintenance means makes the object to be inspected close to the means for moving the object to be inspected at the time of photographing by the imaging means.

In the optical visual inspection system according to the present invention, the thickness of the object to be inspected can also be inspected. That is, on the moving path of the object to be inspected by the object moving means, thickness measuring means for measuring the thickness of the object to be inspected may further be provided. It is preferable that the processing apparatus is configured to detect the thickness defect based on the measured value of the thickness measuring means.

As such a thickness measuring means, a reflection type laser displacement meter can be used, and the defective thickness of the object to be inspected can be inspected from the measurement result of the thickness measuring means. The thickness of the object to be inspected may be obtained from the measurement result of the thickness measuring means, and the position of the line of the image data interpreted by the processing means (the position to be acquired by the image pickup means) may be adjusted.

In addition, the processing means may control the operation of each device constituting the optical visual inspection apparatus of the present invention. For example, the position of the photographing means, the position and brightness of the lighting means, The position of the image data to be acquired at the time of acquisition, and the like. Further, the processing means can judge whether or not there is a defect in the appearance based on the obtained or processed image. At the time of such determination, it is possible to determine an area having a difference in color tone, brightness, and brightness of an image, and specifying the size of the area in the number of pixels or the like. As a result, it is possible to automatically specify an inspection object having an apparent defect based on the determination result of the processing means.

The optical visual inspection apparatus according to the present invention and the optical visual inspection system using the optical visual inspection apparatus are not particularly limited and may be a food such as a crop or aquatic product or a processed product thereof, , Metal plates, electronic parts / products, optical parts / products, and the like. However, it is preferable that the object to be inspected has a shape with a small unevenness in the appearance, and for example, in the case of a plate or a tubular body, defects in the appearance can be more accurately inspected. The object to be inspected may be transparent or opaque.

According to the optical visual inspection apparatus according to the present invention, it is possible to simultaneously acquire image data in a plurality of lines in one imaging unit, thereby reducing the number of imaging units to be used and reducing the number of imaging units to be installed. It is possible to provide an optical appearance inspection apparatus that is miniaturized, and an optical appearance inspection system using the same.

Further, since there is no need to move the photographing means or the illuminating means at the time of acquiring a plurality of image data necessary for the appearance inspection, it is not necessary to take an operation time such as moving these optical devices, And an optical appearance inspection system using the same. Particularly, in the case of using a camera using an image sensor capable of photographing in an arbitrary line, such as a CMOS image sensor as a photographing means, the image processing speed is increased and the inspection time can be further shortened.

In addition, in the optical visual inspection apparatus according to the present invention, the size, height, or thickness of the object to be inspected varies, and only the line for acquiring the image data to be analyzed is selected, and the installation position and angle May not be required. Therefore, even when inspecting an object to be inspected having a different size, height, or thickness, it is possible to provide an optical appearance inspecting device capable of inspecting the appearance of the object to be inspected, eliminating the necessity of conventionally troublesome camera, illumination, An optical visual inspection system using the same is realized.

In the optical visual inspection apparatus according to the present invention, it is possible to acquire a plurality of images necessary for the visual inspection by one shot by the photographing means, and to inspect various types of defects appearing in the appearance of the inspected object by one shot An optical visual inspection apparatus and an optical visual inspection system using the same are realized.

Fig. 1 is an overall configuration diagram showing an optical visual inspection system constituted by using an optical visual inspection apparatus according to the present embodiment.
2 is a perspective view illustrating the appearance inspection station (A) for explaining the contents of processing in the optical visual inspection apparatus, (B) an enlarged plan view showing a degree of light irradiation and reading position on the object to be inspected, 1 is a plan view showing image data to be interpreted by a device.
FIG. 3 is an enlarged view of a main part showing a state in which a sample having a defect is provided on the object to be inspected, (B) a front view showing a defect in an area irradiated with the transmitted light, (C) a front view showing that defects are seen in an outline of an area irradiated with transmitted light, (D) a front view showing that defects are seen in a region in the vicinity of the outline area as an area not irradiated with transmitted light.
Fig. 4 shows an optical visual inspection apparatus according to another embodiment, which is an enlarged principal perspective view of the optical visual inspection apparatus (A), and Fig. 4 (B) shows processing contents for extracting a line- (C) is a plan view showing image data to be analyzed, which is synthesized from an image in a line form.
FIG. 5 is a diagram showing a defect in the case where the object to be inspected is opaque, (A) an enlarged view showing a state in which a sample having a defect is provided in the object to be inspected, (B) (C) a front view showing that a defect is seen in an outline of a region irradiated with light, (D) a front view showing that a defect is seen in a region in the vicinity of the outline region as a region not irradiated with light .
6 is a perspective view showing an inspection method when the object to be inspected is a cylindrical shape.
Fig. 7 is a perspective view showing an inspection method when the object to be inspected is long in the width direction. Fig.
8 is a schematic view showing the principle of the photographing means used in the optical visual inspection apparatus.
9 is a schematic diagram showing the principle of forming image data by the image pickup means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, some embodiments of an optical visual inspection apparatus according to the present invention will be described with reference to the drawings. Particularly, in the embodiment below, the optical appearance inspection device 50 for inspecting the appearance of an industrial product (including parts) is specifically shown. The inspection object W is not limited to this, have.

Fig. 1 is an overall configuration diagram showing an optical visual inspection system 60 constructed using an optical visual inspection apparatus 50 according to the present embodiment. Particularly, in the present embodiment, the inspection object W is plate-shaped and is formed to be transparent, and is configured to be suitable for inspecting the light guide plate as an example.

As shown in Fig. 1, the optical visual inspection system 60 according to this embodiment includes a reception station 10 for receiving a light guide plate as an inspection object W, and the optical visual inspection apparatus 50, An appearance inspection station 20 for inspecting the appearance of the inspection object W, a thickness inspection station 30 for inspecting the thickness of the inspection object W and an unloading station 40 for outputting the inspected object W .

The receiving station 10 receives a work to be inspected W in the optical visual inspection system 60. In this embodiment, since the inspection object W is a light guide plate of a thin plate type, it is liable to cause warping or lifting, and therefore, the appearance inspection station 20 and the thickness inspection station 30, It is preferable that the object to be inspected W is brought into close contact with the object to be inspected 11 by holding means (not shown) so as not to adversely affect the inspection. Such holding means can be realized by a structure for drawing the object to be inspected W toward the object to be inspected or for arranging the object to be inspected W by blowing air from the upper side to the object to be inspected 11. The inspected object W passed from the receiving station 10 is horizontally moved to the subsequent inspection inspection station 20 and the thickness inspection station 30 in a state where the inspection object W is held by the holding means and reaches the unloading station 40 . The holding means may be configured to hold the inspection object W only in the area where the actual inspection is performed, such as the appearance inspection station 20 and the thickness inspection station 30, and only when the inspection is performed.

In addition, various conveyors or the like can be used as the inspection target moving means 11 for transferring the inspection object W to each station. Particularly, since the inspection object W in this embodiment is transparent and the illuminating means 52 being used is transmission illumination, the inspection object moving means 11 for transferring the inspection object W can be provided with the appearance inspection station And passes between the photographing means 51 and the illuminating means 52 installed in the housing 20.

Since the inspection object W is transparent and the imaging means 51 is configured to capture the transmitted light transmitted through the inspection object W as described above, the inspection object moving means 11 and the inspection object W Is preferably constructed so as not to block the space between the photographing means 51 and the illuminating means 52. [ So that the entire inspection object W formed in a transparent manner can be photographed. Specifically, the inspection object moving means 11 can be formed of a transparent material so as not to affect the imaging, or can be configured to carry and maintain a place such as the side of the inspection object W that does not affect the imaging, Further, the holding mechanism of the inspection object W may be formed of a transparent material so as not to affect the imaging, or may be configured to hold the inspection object W by the flow of air.

The visual inspection station 20 performs visual inspection on the object W to be inspected. The optical visual inspection apparatus 50 installed in the visual inspection station 20 includes transmission illumination as illumination means 52 for irradiating light to be transmitted through the object W and illumination light A camera using a CMOS image sensor as the photographing means 51 for photographing the object W to be inspected and a photographing means for photographing the object to be inspected W based on a plurality of lines of image data And a control device as a processing means 53 for judging whether or not an apparent defect in the object W is present is constituted as a main component.

Particularly, since the inspection object W of the present embodiment is a transparent product and the lighting means 52 used is transparent illumination, the imaging means 51 is provided so as to face the illumination means 52, The photographing means 51 is installed such that the photographing direction thereof faces the front of the illuminating direction of the illuminating means 52.

The transmissive illumination used as the illuminating means 52 can emphasize the defect as the object W is irradiated with light. It is preferable that the illuminating means 52 is an LED as a light source in order to secure stable processing performance for a long time and a long term operation. Since the appearance of defects is determined on the basis of image data of a plurality of lines, desirable. The illuminating means 52 may arbitrarily adjust the wavelength of the irradiated light depending on the material and the color of the object W to be inspected. When the object W to be inspected is red, light in a red wavelength range is irradiated, and when the object W is green, light in a green wavelength range can be irradiated. When the object W to be inspected is formed of a material having a high reflectance such as metal or when it is formed of a transparent material, it is preferable to irradiate light in the blue wavelength region. Light in the blue wavelength region is short in wavelength, and reflected light or transmitted light is easily scattered.

It is preferable that the illuminating means 52 is provided in the vicinity of the conveying means for clearly illuminating the object W to be inspected conveyed by the inspected object moving means 11. [ However, in order to adjust the width of the outline of the area illuminated by the illumination means 52 or to adjust the brightness of the illuminated area, the illuminating means 52 is provided with the inspection object moving means 11, May be provided so as to be able to arbitrarily adjust the interval between the two.

The camera used as the photographing means 51 is provided with a CMOS image sensor as an image pickup element and a surface-mounted image pickup element in which a plurality of photodiodes are vertically and horizontally arranged. For example, an image pickup device having 2048 pixels in the horizontal direction (width direction with respect to the scanning direction) and 2048 pixels in the vertical direction (scanning direction) can be used. In the photographing means 51 provided with such an image sensor, when the lateral field of view is 200 mm, the field of view in the vertical direction is 200 mm. Therefore, a plurality of photodiode columns to be used for photographing are designated , It is possible to acquire image data on a plurality of lines by scanning the corresponding imaging means 51. Further, by changing the position (line) of the photodiode column used for photographing within the field of view in the vertical direction, it is possible to operate as if a plurality of line sensors are used, and also by the opening angle of the angle of view It is possible to change the angle.

Then, the control device used as the processing means 53 acquires the photographed image photographed by the photographing means 51, analyzes each of the image data of a plurality of lines, and judges whether or not the image is defective in appearance. The image data to be used for this analysis may be one in which the photographed image photographed by the photographing means 51 is used as it is, and the photographed image is developed into a plane image by a plurality of lines. Therefore, the processing means 53 is constituted by a CPU (Central Processing Unit) and a memory for performing numerical calculation and information processing necessary for image processing as needed while interpreting the image data. A computer may be used as such a processing apparatus, but it may be a device designed for numerical calculation and information processing necessary for analyzing and judging image processing and apparent defects. The processing means 53 can also control which column of the photodiode array arranged in the scanning direction of the imaging means 51 is to be photographed by the imaging device.

It is also possible to detect the horizontal movement distance and the movement speed of the inspection object W by the inspection object moving means 11 in order to correlate the photographed image acquired by the photographing means 51 with the photographing position of the object W to be inspected It is preferable to provide the detection means 54. [ As the transport detection means 54, a rotary encoder, a linear encoder, or the like can be used. The conveyance detecting means 54 can be installed at any place in the conveyance path of the inspection object W. Preferably, in order to accurately measure the horizontal movement distance and speed of the inspection object W, Is installed in the station (20), particularly preferably in the vicinity of the photographing area of the photographing means (51). By sending the detection signal from the conveyance detecting means 54 to the processing means 53, it is possible to suppress the unevenness of the photographing disassembly ability due to the fluctuation of the moving speed of the inspection object W by the inspection object moving means 11 And the positional correction can be made possible when the image obtained in the form of a line in the photographing means 51 is developed into image data (plane image) used for the analysis.

Then, the thickness inspection station 30 checks whether the thickness of the object to be inspected W is within the predetermined range. That is, in this thickness inspection station 30, the thickness of the inspection object W conveyed by the inspection object moving means 11 is measured by the thickness detection means 31 comprising a reflection type laser displacement meter. The measurement result is sent to the processing means (53), and the processing means (53) can detect a defect in the thickness of the object to be inspected (W).

Further, the optical visual inspection system 60 shown in Fig. 1 is configured so that the object W to be inspected is transparent, and the photographed image is acquired by transmission illumination. That is, the illumination means 52 is provided on the opposite side with the object to be inspected therebetween. At this time, if the object W to be inspected is not transparent, image data can not be acquired by the transmission illumination. Therefore, when the object W to be inspected is opaque, reflection light is used as shown in Fig. 4, which will be described later, and the image pickup means 51 acquires the image data by taking reflected light of the light irradiated to the inspection target portion . At this time, it is preferable that the illuminating means 52 irradiate light to the object W to be inspected in the photographing direction by the photographing means 51, and it is particularly preferable to irradiate light vertically upward of the object to be inspected W .

Next, with reference to Fig. 2, processing contents in the optical visual inspection apparatus 50 at the visual inspection station 20 will be described. 2 (A) is a perspective view showing the appearance inspection station 20, FIG. 2 (B) is an enlarged plan view of a main part showing a light irradiation state and a reading position with respect to the inspection object W, Fig. 6 is a plan view showing image data to be analyzed by the processing apparatus. Fig.

First, in the visual inspection station 20, the inspection object W is transported by the inspection object moving means 11 such as a conveyor, and illuminating means 52 is provided below the inspection object moving means 11 Is installed. The lighting means 52 irradiates light over the entire width direction (direction intersecting the conveying direction) of the inspection object W with line illumination. The light of the illumination means 52 is transmitted through the object W so that the imaging means 51 provided above the object W can take the transmitted light of the object W to be inspected. Then, the inspection object W passes between the illuminating means 52 and the photographing means 51.

As shown in Fig. 2 (B), the photographing means 51 has a bright region A1, an outline region A2 thereof, an area not irradiated with the transmitted light, Image data photographed in a line extending in the width direction (direction intersecting the scanning direction) of the inspection object W is acquired in the area A3 in the neighborhood area. The photographing in each line is carried out while conveying the inspection object W, and is photographed every time it is moved by the number of pixels acquired by at least one photographing. The conveyance distance of the inspection object W is detected by the conveyance detecting means 54 such as the rotary encoder. Therefore, at the time when a signal indicating that the camera has moved a certain distance is acquired by the conveyance detecting means 54, the photographing means 51 can photograph an image on a predetermined line.

2 (B) is performed with respect to the whole of the inspection object W, and then the image of the line shape photographed every time the inspection target moves, The image data D1 to D3 developed in the same plane image as the image data D1 to D3 are formed. That is, the image data D1 formed by the image of the bright region A1 and the image formed by the captured image of the outline region A2 of the bright region A1 in the region illuminated by the transmitted light The image data D3 formed by the captured image of the data D2 and the region A3 in the vicinity of the outline region which is not irradiated with the transmitted light is formed. In the formation of such image data, the processing device acquires an image in the form of a line every time the image pickup means 51 picks up the image, and develops the image in the form of a face image, It may be sent to the processing means 53 after being synthesized into a face image. Each surface image (image data) in each of the lines thus formed is obtained by photographing a state in which the irradiation direction of light to the inspection object W is different. Therefore, it is possible to acquire image data which can be obtained by one scanning in the photographing means 51, but which is different in the angle of light emission and is scanned the photographing means 51 several times.

Next, with reference to Fig. 3, an example will be described in which various defects are inspected by using image data in a plurality of lines of different light irradiation states. Fig. 3 (A) is an enlarged view of the main part showing a state in which a sample of defects is provided on the inspection object W, Fig. 3 (B) is a front view showing defects in the area irradiated with the transmitted light, 3C is a front view showing that defects are seen in the outline of the area irradiated with the transmitted light, and FIG. 3D is a front view showing that defects are seen in the area in the vicinity of the outline area.

In this example, the object to be inspected W is transparent, and in Figs. 3 (B) to 3 (D), the object to be inspected W is visible from the light transmitted through the object. As shown in Fig. 3A, the inspection object W is provided with a scratch defect F1 such as a scratch present on the surface in order from the top, a color defect F2 having a black foreign substance on the surface or inner surface, , And an irregular defect (F3) composed of gentle irregularities on the surface is formed.

As shown in Fig. 3 (B), in the sample inspection object W in which such a defect is formed, the color defect F2 clearly appears in the region A1 in which light is irradiated on the back side, F1) and irregular defect (F3) do not clearly appear. In addition, as shown in Fig. 3 (C), the uneven defect F3 appears clearly in the contour area A2, while the color defect F2 and the wound defect F1 do not clearly appear. 3 (D), the wound defect F1 clearly appears in the region A3 where light is not irradiated, while the color defect F2 and the irregular defect F3 are clearly Is not emerging.

Since the types of defects clearly appearing in relation to the region irradiated with light are different from each other, the image data on the plurality of lines are respectively analyzed so that a plurality of image defects Can be inspected.

In the above-described embodiment, the inspection object W is a transparent product, so that transmission illumination is used as the illumination means 52. However, when the inspection object W is opaque, Means may be provided on the side of the photographing means 51 and the photographing means 52 may photograph the reflected light of the light irradiated on the object to be inspected W. In the above embodiment, a camera using a CMOS image sensor is used as the photographing means 51, but a camera using a CCD image sensor that photographs a predetermined area as a face image may be used. In this case, Image processing such as line-shaped image extraction as shown in Fig. 4 is performed.

4 shows an optical visual inspection apparatus 150 according to another embodiment and the optical visual inspection apparatus 150 is also installed in the visual inspection station 20 of the optical visual inspection system 60 shown in FIG. . The optical visual inspection apparatus 150 shown in this embodiment uses a camera using a CCD image sensor as the photographing means 151 and the illumination means 152 is configured to photograph reflected light instead of transmitted light. 4A is a schematic perspective view showing an optical appearance inspection apparatus 150 according to another embodiment, and FIG. 4B is a conceptual diagram showing processing contents for extracting a line-shaped image from a plurality of lines in a photographed image And FIG. 4C is a plan view showing image data to be analyzed, which is synthesized from an image in a line form.

In this embodiment as well, the object W to be inspected is conveyed by the inspection object moving means 11 such as a conveyor. The inspected object W that has been conveyed is irradiated with light from the lighting means 152 provided above the inspected object W. The photographing means 151 provided above the object W to be inspected, as in the case of the illuminating means 152, includes at least an irradiated area irradiated with light and an area in the vicinity of the irradiated area, And the whole object in the width direction of the inspection object W comes out to take an image. The photographed image is associated with a conveyance distance measured by a conveyance detecting means such as a rotary encoder, as in the above-described embodiment.

Then, as shown in Fig. 4 (B), an image in a line form is extracted in an arbitrarily set area in an image taken in a constant area. That is, the area A1 and the outline area A2, which are illuminated by the light emitted from the illumination unit 152, and the area A3, which is not irradiated with light, (L1 to L3) are extracted. That is, a line-shaped image L1 is extracted from a region A1 that is irradiated with light, a line-shaped image L2 is extracted from an outline region A2 of the region A1 that is irradiated with light, The image L3 in the form of a line is extracted from the area A3 in the vicinity of the contour area which is not irradiated.

Then, the image data of the extracted line image is synthesized with the image data of the plane image as shown in Fig. 4 (C). That is, the image data D11 obtained by extracting the line-shaped image L1 extracted from the region A1 illuminated by light and the line-shaped image D11 extracted from the outline region A2 of the region A1, The image data D13 which is the image data D12 which is connected to the image L2 and the image L3 which is the line-shaped image obtained by subtracting the image data D12 from the region A3 in which the light is not irradiated and which is the outline region are synthesized. Then, it is possible to judge whether or not each appearance defect in the inspection object W is analyzed by analyzing the change in color and / or brightness with respect to each of the synthesized surface images (image data).

Next, referring to Fig. 5, a description will be given of a case where defects are observed when the inspection object W is opaque. 5A is a magnified view showing a state in which a sample of defects is provided on the object to be inspected W, FIG. 5A is an enlarged view of FIG. 5A, 5B is a front view showing defects in a region irradiated with light, FIG. 5C is a front view showing defects in an outline of a region irradiated with light, FIG. Is a non-irradiated area and shows defects in the vicinity of the contour area.

In this example, the object W to be inspected is opaque, and FIGS. 5B to 5D show that the object W is visible from the reflected light when the object W is irradiated with light. 5A, a hole defect F12 such as a foreign particle defect F11 such as a black foreign substance present on the surface, a through hole or the like passing through the surface of the inspection object W, , A scratch defect (F13) such as a scratch present on the surface is formed.

In the sample inspection object W in which such a defect is formed, the hole defect F12 clearly appears in the region A1 where light is irradiated on the surface as shown in Fig. 5B, and the foreign matter defect F11 ) And wound defect (F13) do not appear clearly. 5 (C), the foreign matter defect F11 clearly appears in the contour area A2, while the hole defect F12 and the wound defect F13 do not clearly appear . 5 (D), the wound defect F13 clearly appears in the region A3 where light is not irradiated, and the foreign matter defect F11 and the hole defect F12 are clearly It does not appear.

Even if the object to be inspected is opaque as described above, the kind of defects clearly appearing in the relationship with the region irradiated with light by taking reflected light is different. Therefore, by analyzing the image data on the plurality of lines, it is possible to inspect various appearance defects using a plurality of image data obtained by one scanning.

In the present embodiment, the case where the object to be inspected W is opaque has been described, but in the case of being transparent, the illumination means 52 for irradiating the transmission illumination as shown in Fig. 2 can be used. Further, as described in the present embodiment, even when the object to be inspected W is opaque, the imaging means 51 comprising a camera using a CMOS image sensor can be used as described above. In this case, The defect can be inspected by developing the image as a face image.

Fig. 6 is a perspective view showing an inspection method in the case where the inspection object W has a cylindrical shape. As shown in this figure, when the inspection object is a tubular shape, and the appearance on the peripheral surface is inspected, the inspection can be performed by rotating the inspection object W about the axis. In particular, when the object W to be inspected has a curved surface, the problem of distortion of the image on the curved surface can be solved by using the camera using the CMOS image sensor as the photographing means 51, and more accurate visual inspection can be performed. In this embodiment, however, a camera using a CCD image sensor may be used as the photographing means.

Fig. 7 is a perspective view showing an inspection method when the inspection object W is long in the width direction, that is, in the direction perpendicular to the conveyance direction. As shown in this figure, when the subject to be inspected is wide, a plurality of photographing means 51 can be used side by side in the width direction. In this case, several sets of photographing means 51 are used. However, in any range of the width direction, image data of a plurality of lines is acquired by any one of the photographing means (51). Although the photographing means 51 is arranged in a line in Fig. 7, the photographing means 51 may be arranged in a staggered form. However, it is necessary to be able to specify the photographing range so that the photographing area can be connected to the photographing area in the width direction without any gaps. In this embodiment, however, a camera using a CCD image sensor may be used as the photographing means.

According to the optical visual inspection apparatus configured as described above, it becomes possible to simultaneously inspect all the defects occurring in the manufacturing process of the inspection object W by one imaging operation under one imaging condition, , It is possible to analyze and determine defects by acquiring image data necessary for inspection without physically adjusting optical systems such as photographing means and illumination means even in the case of products having different thicknesses.

Next, referring to Figs. 8 and 9, a description will be given of photographing means suitably used in the optical visual inspection apparatus according to the present embodiment. Fig. Such a photographing means is constituted by arranging a plurality of photodiode arrays in which a plurality of photodiodes are arranged in a direction crossing the scanning direction, in a parallel manner and in a plurality of scanning directions as shown in Fig. FIG. 8 shows four rows of photodiodes made up of A to D columns, and each row is made up of nine photodiodes arranged in the arrangement direction. By photographing with such a photographing means constructed in this way, it is possible to photograph an image of 4 lines x 9 pixels in total 36 pixels.

In particular, the imaging means according to this embodiment further comprises an image processing section, and the image processing section performs processing for reducing the image size of 36 pixels. More specifically, a process of calculating or extracting pixels of luminance with preset conditions such as maximum luminance, minimum luminance, and average luminance from the pixels arranged in the scanning direction is executed for all the pixels arranged in the arrangement direction. Based on such conditions, image data of one column connected to the pixels calculated or extracted is generated, and the image data of the one column is used for surface inspection. Fig. 8 shows an array of photodiodes. When the photodiodes are viewed as pixels photographed by the photodiodes, the pixels with the lowest luminance are extracted. 8, when the arrangement of the photodiodes is regarded as an arrangement of pixels, the B1 pixels having the lowest luminance in the pixels A1 to D1 are extracted and the C2 pixels having the lowest luminance even in the pixels A2 to D2 arranged side by side are extracted . This calculation or extraction processing is executed up to the pixels of A9 to D9 to generate one row of image data composed of the pixels of B1, C2, A3, B4, C5, D6, B7, C8 and A9. As a result, it is possible to synthesize an image of 36 pixels into image data of 9 pixels, thereby reducing the amount of data and increasing the processing speed. The extraction of the associated pixel may also be performed by the processing means.

Fig. 9 is a schematic diagram showing a process of calculating and extracting image data of one column in an image actually taken of an inspection object. As shown in Fig. 9 (A), the object to be inspected W is photographed and an image composed of pixels in 10 rows arranged in the scanning direction is photographed. Each column can be composed of pixels corresponding to optical elements. Then, as shown in Fig. 9 (B), pixels of the respective rows arranged in the scanning direction in the photographed pixels are compared to extract pixels having the highest luminance as shown in Fig. 9 (C). By performing this processing up to the arrangement direction of the pixels in each column and combining the extracted pixels in one column, it is possible to generate one column of image data. Then, the generated image data of one column is used for the inspection and used for the inspection, whereby the image data used for the inspection can be greatly reduced and the processing speed can be improved.

In the inspection apparatus using such a photographing means, the inspection distance can be increased by setting the distance of the object to be inspected to the number of pixels of the image taken approximately one time. That is, in FIG. 9, by scanning the object to be inspected for 9 pixels or 10 pixels, it is possible to inspect a large number of objects to be inspected by increasing the distance of travel for each one shot.

On the other hand, when the conveying distance of the inspection object is made shorter than the pixel train photographed in one shot, it is possible to acquire an image for a wide range including its surroundings with respect to any area. For example, as shown in FIG. 9, when 10 rows of photodiodes are arranged side by side in the scanning direction, 1 to 5 rows of the photodiodes can be photographed. Further, it is possible to acquire more precise image data without missing a shot, from extracting a pixel (a condition-setting pixel) satisfying the purpose out of the shooting pixels. Therefore, in this case, the surface inspection can be accurately performed.

[Industrial Availability]

The optical visual inspection apparatus according to the present invention can be used not only for industrial products but also for inspection of defects in appearance of various articles such as raw materials, crops, marine products, and processed products thereof. Then, the inspection object W can be visually inspected even if it is transparent or opaque.

10; Receiving station
11; The inspection object moving means
20; Appearance inspection station
30; Inspection station
31; Detection means
40; Export station
50, 150; Optical visual inspection system
51,151; Shooting means
52,152; Lighting means
53; Processing means
54; The conveyance detecting means
60; Optical visual inspection system
W; Inspection object

Claims (11)

An imaging apparatus for use in an optical visual inspection apparatus for determining an apparent defect in an image of an object to be inspected while scanning the object,
An image capturing unit that captures an image of a plurality of lines arranged in a scanning direction of an object to be inspected and a plurality of lines that are captured by the image capturing unit and compares the color and / or brightness with respect to each region in a direction orthogonal to the scanning direction, And an image processing unit for extracting a specific line area on the basis of the combined image data and combining the combined image data with one line image data.
The image pickup apparatus according to claim 1,
And processing means for analyzing and judging whether or not there is an apparent defect in the inspection object using the photographed image photographed by the photographing means,
The processing means analyzes a change in color and / or brightness with respect to image data on a plurality of lines each of which is selected in an area where the intensity of light irradiated to the inspection object is different while acquiring a photographed image from the imaging means, And judges whether or not each appearance defect in the object is judged.
3. The method of claim 2,
Further comprising illumination means for irradiating light to the object to be inspected,
Wherein the image data on a plurality of lines analyzed by said processing means is selected in each of the regions irradiated by the illuminating means and the regions irradiated by the illuminating means.
3. The method of claim 2,
Further comprising illumination means for irradiating light to the object to be inspected,
The image data in a plurality of lines analyzed by the processing means is divided into an irradiation center region which is a center portion of the region irradiated with the light by the illumination means, a contour region of the region irradiated with the light by the illumination means, And a non-irradiated region which is in the vicinity of the region and is not irradiated with light by the illumination means.
3. The method of claim 2,
Further comprising illumination means for irradiating light to the object to be inspected,
The image data in a plurality of lines analyzed by the processing means is a high luminance region having the highest luminance of light irradiated to the object to be inspected, a luminance change region in which the luminance is abruptly changed, and a luminance change region And a low-luminance stable region in which the change in the luminance is stable, is selected in at least two or more regions.
6. The method according to any one of claims 2 to 5,
The image data interpreted by the processing means is a plurality of plane images obtained by scanning the photographing means to acquire a plurality of line-shaped images photographed respectively on a plurality of lines,
Wherein the acquisition of the image data of a plurality of lines by the processing means is performed by one scanning in the photographing means.
7. The method according to any one of claims 2 to 6,
Wherein the photographing means is an image sensor camera for scanning the object to be inspected in a predetermined direction,
Wherein the image data on a plurality of lines analyzed by the processing means is an image of an optical appearance which is a cotton image developed by combining an image photographed in a line form extending in a direction crossing the scanning direction, Inspection device.
8. The method according to any one of claims 2 to 7,
Wherein the photographing section photographs a plurality of lines arranged in the scanning direction of the inspection object in each of a plurality of lines respectively selected from the areas of different intensity of light irradiated to the inspection object,
And a plurality of image data of one line synthesized by the image processing unit are respectively used as image data in a plurality of lines analyzed by said processing means.
9. The method according to any one of claims 2 to 8,
Wherein the photographing means comprises an image adjusting means for making an offset value and / or a gain value different for each region of the inspection target object having different intensity of light.
An optical visual inspection system configured by using the optical visual inspection apparatus according to any one of claims 2 to 9,
And a conveyance detecting means for detecting a moving speed or a moving distance of the object to be inspected by the object to be inspected moving means,
Wherein the photographed image acquired by the processing means is associated with the photographed position calculated based on the moving speed or the movement amount acquired by the conveyance detecting means.
11. The method of claim 10,
Wherein the inspection object moving means comprises a holding means for sucking the inspection object to be placed and carried or to tightly close the inspection object, wherein the thickness of the inspection object is measured on the movement path of the inspection object in the inspection object moving means Thickness measuring means for measuring the thickness of the substrate,
Wherein the processing means detects a defect in thickness based on the measured value of the thickness measuring means.

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