Multi-surface imaging system, and multi-surface appearance inspection system and appearance inspection method using same

Abstract

The present invention achieves, by one imaging process, the entire-circumference inspection and multi-surface inspection that would require multiple imaging means, thereby reducing the size and installation costs of an inspection system.　Provided is a multi-surface imaging system comprising: an imaging module (1) that is provided with an illumination means (15) which illuminates an object to be imaged W, and a plurality of imaging units (10) which are disposed apart from each other around the object to be imaged; an imaging unit control unit (22) that controls the imaging units; an imaging control unit (2) that is provided with an image synthesis unit (21) which creates a single synthesized image by synthesizing a plurality of image signals, from the object to be imaged, acquired by the plurality of imaging units; and a communication means (3) that connects the imaging module and the imaging control unit. The maging units each comprise: an imaging means; a plane mirror that is disposed on an optical axis of the imaging means and is rotatable with respect to the optical axis; and an imaging means holding unit that holds the imaging means and the plane mirror.

Description

Multi-plane imaging system, and multi-plane visual inspection system and visual inspection method using the same.

[0001] The present invention relates to a ring imaging system for imaging the inner and outer surfaces of a three-dimensional article from multiple angles, as well as a visual inspection system and a visual inspection method using the same.

[0002] Three-dimensional objects with inner and outer surfaces, such as beverage containers with openings on the top surface, and annular components like O-rings and screw washers, are subject to visual inspection because their appearance quality is crucial. Beverage containers have product names and other type indications printed on their outer surface, and are also decorated to enhance their appearance and functionality. Therefore, the state of decoration, such as printing, coloring, and painting, is inspected by capturing images of the outer surface of the container. In addition, the opening and interior of the container must also be inspected for scratches, foreign objects, etc., by capturing images of the inner surface. Annular components also need to be inspected for scratches on their inner and outer surfaces. However, inspecting three-dimensional objects with inner and outer surfaces from multiple angles requires the installation of multiple imaging and lighting means, resulting in a large overall inspection system, high equipment costs, and a large installation space.

[0003] Patent Document 1 discloses an inspection apparatus for a three-dimensional shaped object, which includes an optical system that acquires a plurality of optical images of the three-dimensional shaped object to be inspected, a photoelectric conversion means that electrically converts the incident optical image, and an optical propagation means that supplies the optical images acquired by the plurality of optical systems to the photoelectric conversion means as an optical image for one screen. Further, an inspection apparatus is also disclosed that includes an imaging device, a plurality of imaging means each consisting of a mirror that projects an optical image of the three-dimensional shaped object to be inspected from multiple aspects by changing the reflection angle onto the imaging device, and an image processing means that integrates the imaging results of the plurality of imaging means onto one screen. Patent Document 2 discloses an appearance inspection apparatus that includes a plurality of imaging means each consisting of a camera and a mirror that image the perspective image of the inspection object from different directions, and a display means that displays each perspective image imaged by the plurality of imaging means. Patent Document 3 discloses an inspection apparatus that includes a reflection part arranged at a distance from the side of a container, an imaging part that images the decorative part of the container through the reflection part, and an inspection part that inspects the decorative part based on the image imaged by the imaging part. However, Patent Document 3 is an invention that avoids the installation space of the entire apparatus spreading horizontally even when the optical path length from the container to the imaging part is increased by passing through the reflection part, and does not disclose imaging the inner and outer circumferential surfaces of the container from multiple aspects.

[0004] Japanese Patent Application Laid-Open No. 6-160038 Japanese Patent Application Laid-Open No. 11-304721 Japanese Patent Application Laid-Open No. 2021-105554

[0005] The invention of the present application is to aggregate a plurality of images output from a plurality of imaging means into a single composite image, making it substantially equivalent to a single image acquired by a single imaging means, thereby realizing a full circumference inspection or a multi-faceted inspection that requires a plurality of imaging means through one image processing, compactifying the inspection system, and reducing the equipment cost.

[0006] The problems of the invention of the present application can be solved by the following aspects (1) to (7). Specifically,

[0007] (Aspect 1) A multi-plane imaging system comprising: an imaging unit having illumination means for illuminating an object to be imaged and a plurality of imaging units arranged spaced apart around the object to be imaged; an imaging unit control unit for controlling the imaging units; an imaging control unit having an image synthesis unit for synthesizing a plurality of image signals from the object to be imaged acquired by the plurality of imaging units to create a single composite image; and a communication means for connecting the imaging unit and the imaging control unit, wherein the imaging unit comprises an imaging means, a plane mirror arranged on the optical axis of the imaging means and rotatable with respect to the optical axis, and an imaging means holding unit for holding the imaging means and the plane mirror. The image synthesis unit can consolidate a plurality of images output from a plurality of imaging means into a single composite image using an FPGA (Field-Programmable Gate Array), thereby making it substantially equivalent to a single image acquired from a single imaging means. As a result, full-circumference inspection and multi-plane inspection that would otherwise require multiple imaging means can be realized with a single image processing, making the imaging system more compact and reducing equipment costs. Furthermore, by arranging multiple imaging units, each combining an imaging means and a plane mirror, at intervals around the object to be imaged, it is possible to arbitrarily select and image the inner and outer surfaces of the object.

[0008] (Aspect 2) The imaging unit is a multi-plane imaging system as described in Aspect 1, characterized in that it can be moved independently and individually up, down, left, and right by the imaging unit control unit. By moving the imaging unit independently and individually up, down, left, and right, the inner and outer surfaces of the object to be imaged can be arbitrarily selected and imaged, and the workpiece diameter can be easily accommodated.

[0009] (Aspect 3) The multi-plane imaging system according to either aspect 1 or 2, characterized in that the illumination means uses either surface illumination or pseudo-coaxial incident illumination alone or in combination. By employing surface illumination as the illumination means, a uniform illumination light can be irradiated onto the object to be inspected. Furthermore, by employing coaxial incident illumination, the illumination light can be irradiated onto the object to be imaged from a direction coaxial with the imaging direction of the imaging means.

[0010] (Aspect 4) A multi-faceted visual inspection system comprising: an inspection unit comprising illumination means for illuminating an object to be inspected, transport means for transporting the object to be inspected, and a plurality of imaging units arranged spaced apart around the object to be inspected; an imaging unit control unit for controlling the imaging units; an image synthesis unit for synthesizing a plurality of image signals from the object to be inspected acquired by the plurality of imaging units to create a single composite image; an inspection control unit comprising an image processing unit for image processing the composite image created by the image synthesis unit and a determination unit for determining the inspection image processed by the image processing unit; and a communication means for connecting the inspection unit and the inspection control unit, wherein the imaging unit comprises imaging means, a plane mirror arranged on the optical axis of the imaging means and rotatable with respect to the optical axis, and an imaging means holding unit for holding the imaging means and the plane mirror. The image synthesis unit can aggregate a plurality of images output from a plurality of imaging means into a single composite image using an FPGA (Field-Programmable Gate Array), making it substantially equivalent to a single image acquired from a single imaging means, and image processing in the image processing unit and pass / fail determination in the determination unit can be realized by a single image processing unit. This allows for the realization of 360-degree and multi-face inspections, which would otherwise require multiple imaging devices, using a single image processing unit, thereby enabling a more compact visual inspection system and reducing equipment costs. Furthermore, by arranging multiple imaging units, each combining an imaging device and a plane mirror, at intervals around the object being inspected, it becomes possible to arbitrarily select and inspect the inner and outer surfaces of the object.

[0011] (Aspect 5) The imaging unit is a multi-faceted visual inspection system as described in Aspect 4, characterized in that it can be moved independently and individually up, down, left, and right by the imaging unit control unit. By moving the imaging unit independently and individually up, down, left, and right, the inner and outer surfaces of the object to be inspected can be arbitrarily selected and imaged, and the workpiece diameter can be easily accommodated.

[0012] (Aspect 6) The multi-faceted visual inspection system according to either aspect 4 or aspect 5, characterized in that the illumination means uses either surface illumination or pseudo-coaxial incident illumination alone or in combination. This is because surface illumination can be used as the illumination means to irradiate the object to be inspected with uniform illumination light. Furthermore, by using coaxial incident illumination, illumination light can be irradiated onto the object to be inspected from the same axis as the imaging direction of the imaging means.

[0013] (Aspect 7) An appearance inspection method using a multi-face appearance inspection system as described in any of Aspects 4 to 6, comprising: an imaging condition setting step in which, based on the appearance of the object to be inspected, the arrangement of the lighting means and the imaging unit control unit set the vertical position of each of the multiple imaging units, the angle and position of the plane mirror, and the optical path length between the imaging means and the plane mirror; an inspection image synthesis step in which an inspection image is created by receiving reflected light from the object to be inspected and synthesizing multiple image signals acquired by the multiple imaging units; a plane image extraction step in which a plane image is created from the inspection image synthesized in the inspection image synthesis step; a pre-processing step in which the plane image is corrected; a feature extraction step in which features are extracted from the corrected plane image; a post-processing step in which the feature extracted inspection image is corrected; a blob analysis step in which the corrected inspection image is subjected to blob analysis; and an inspection image determination step in which the pass or fail of the inspection image is determined based on the inspection image subjected to blob analysis.

[0014] According to the present invention, by integrating multiple images output from multiple imaging means into a single composite image, it is made substantially equivalent to a single image acquired from a single imaging means. This enables full-circumference inspection and multi-face inspection, which would otherwise require multiple imaging means, to be realized with a single image processing, thereby making the inspection system more compact and reducing equipment costs. Furthermore, by arranging multiple imaging units, each combining an imaging means and a plane mirror, in a circular arrangement around the object to be imaged, the inner and outer surfaces of the object can be arbitrarily selected and imaged.

[0015] This is a diagram illustrating the configuration of the multi-plane imaging system of the present invention. This is a side view showing one embodiment of the imaging unit constituting the multi-plane imaging system of the present invention. This is a cross-sectional view (A-A') illustrating an embodiment of imaging by the multi-plane imaging system of the present invention. This is a photograph showing an image of an annular member captured by the multi-plane imaging system of the present invention. This is a photograph showing an image of a container captured by the multi-plane imaging system of the present invention. This is a diagram illustrating the configuration of the multi-plane appearance inspection system of the present invention. This is a flowchart explaining the inspection flow of the multi-plane appearance inspection system of the present invention. This is a cross-sectional view (A-A') illustrating an inspection mode of the multi-plane appearance inspection system of the present invention.

[0016] A description of an embodiment for carrying out the present invention will be given with reference to Figures 1 to 8. However, Figures 1 to 8 are just examples of embodiments and are not limited thereto. For example, the arrangement of the imaging unit is not limited to those arranged equidistant from the object to be imaged (in a circular pattern), but also includes arrangements that are not equidistant from the object to be imaged.

[0017] A. Multi-plane imaging system 1. Diagram 1 of the multi-plane imaging system is a diagram illustrating one embodiment of the multi-plane imaging system 100 of the present invention. The multi-plane imaging system 100 of the present invention consists of an imaging unit 1 in which a plurality of imaging units 10 are arranged spaced apart around an object to be imaged W, an imaging control unit 2, and a communication means 3 connecting the imaging unit 1 and the imaging control unit 2. The imaging unit 1 consists of an illumination means 15 for illuminating the object to be imaged W, and a plurality of imaging units 10 arranged spaced apart so as to surround the object to be imaged W at a predetermined distance from the center line of the object to be imaged W. The imaging control unit 2 includes an image synthesis unit 21 that synthesizes a plurality of image signals acquired by each of the plurality of imaging units (10a to 11f) as a single composite image, an imaging unit control unit 22 that controls the imaging units 10, and an information storage unit 23. The following will be described in the order of the object to be imaged W, the imaging unit 1, the imaging control unit 2, and the communication means 3.

[0018] 2. Objects to be Imaged The objects to be imaged W of the multi-face imaging system 100 of the present invention are not particularly limited as long as they are three-dimensional objects having inner and outer surfaces. Specifically, these include cylindrical bodies with an opening on the top surface (e.g., beverage containers such as cans and bottles) and containers with decorations such as printing, coloring, painting, or unevenness on the outer surface, and annular members having inner and outer surfaces (e.g., O-rings and screw washers). Cylinders and annular members with an opening on the top surface may require imaging of both the inner and outer surfaces, and imaging both the inner and outer surfaces simultaneously can shorten the imaging time and simplify the imaging equipment.

[0019] 3. Imaging Unit The imaging unit 1 that constitutes the multi-plane imaging system 100 of the present invention comprises an illumination means 15 and an imaging unit 10.

[0020] (3-1) Illumination means The form of the illumination means 15 of the multi-face imaging system 100 of the present invention can be appropriately selected depending on the form of the object to be imaged W. Specifically, planar illumination, bar illumination, annular illumination, dome illumination, spot illumination, and coaxial reflected illumination consisting of a housing that houses a light source and a half mirror can be employed. When coaxial reflected illumination is employed, illumination light is irradiated onto the object to be imaged W from a direction coaxial with the imaging direction of the imaging means 11 via the half mirror. In the case of annular illumination, the illumination means 15 is preferably placed directly above the object to be imaged W, and in the case of planar illumination, it can be appropriately placed directly above, on the side, or below the object to be imaged W.

[0021] (3-2) Imaging Unit Figure 2 is a side view showing one embodiment of the imaging unit 10 that constitutes the multi-plane imaging system 100 of the present invention. The imaging unit 10 consists of an imaging means 11, a plane mirror 13 that projects reflected images of the object to be imaged W viewed from multiple sides onto the imaging means 11 by changing the reflection angle, an imaging unit holding part 12 that holds the imaging means 11 and the plane mirror 13, and an imaging unit drive part 14 which is located below the imaging unit holding part 12 and drives the imaging unit holding part 12 up, down, left, and right. The rotation angle (θ) of the plane mirror 13 and the up, down, left, and right movement of the imaging unit holding part 12 by the imaging unit drive part 14 are controlled by the imaging unit control part 22 of the imaging control unit 2. Figure 3 is a cross-sectional view (A-A') illustrating an embodiment of imaging by the multi-plane imaging system 100 of the present invention. Figure 3(a) shows an image of the outer surface of the object to be imaged W, Figure 3(b) shows an image of the outer and inner surfaces of the object to be imaged W, and Figure 3(c) shows an image of the bottom and the outer surface of the opening of the object to be imaged W.

[0022] (3-2-1) Imaging means The imaging means 11 constituting the imaging unit 10 of the present invention uses an integrated circuit (IC) that converts reflected light into an image signal, specifically a photodiode arranged on a planar silicon substrate, and an integrated circuit such as a charge-coupled device (CCD) or complementary metal oxide semiconductor (CMOS) is used for transfer. It is composed of an optical system that forms an image of the workpiece on the imaging surface of the solid-state image sensor, and a signal processing circuit that processes the output of the solid-state image sensor to obtain a brightness value for each pixel. Depending on the nature of the object to be inspected W, an area camera or a line scan camera can be appropriately selected. When the object to be imaged W is stationary, an area camera can be suitably used. When the object to be imaged W is moving continuously, a line camera can be suitably used.

[0023] (3-2-2) Planar mirror The plane mirror 13 constituting the imaging unit 10 of the present invention is positioned directly below the optical axis of the imaging means 11 and plays the role of irradiating the imaging means 11 with reflected light from the object to be imaged W. By controlling the rotation angle (θ) of the plane mirror 13, the reflection angle of the reflected light from the object to be imaged W can be changed, thereby irradiating the imaging means 11 with reflected light from any inner or outer surface of the object to be imaged W.

[0024] (3-2-3) Imaging Unit Holding Part The imaging unit holding part 12, which constitutes the imaging unit 10 of the present invention, is responsible for holding the imaging means 11 and the plane mirror 13, and for changing the distance (L) between the imaging means 11 and the plane mirror 13. In addition, the imaging unit driving unit 14 drives the imaging unit holding part 12 itself up, down, left, and right.

[0025] (3-2-4) Imaging Unit Drive Unit The imaging unit drive unit 14, which constitutes the imaging unit 10 of the present invention, also plays a role in driving the imaging unit holding unit 12 itself up, down, left, and right. It is controlled by the imaging unit control unit 22 of the imaging control unit 2.

[0026] 4. Image Processing Control The image processing control unit 2 that constitutes the multi-plane imaging system 100 of the present invention comprises an image synthesis unit 21, an imaging unit control unit 22, and an information storage unit 23, and may also include a display device 24 and an input device 25, which are various interfaces for input and output.

[0027] (4-1) Image Synthesis Unit The image synthesis unit 21, which constitutes the imaging control unit 2 of the present invention, is made up of a board equipped with an FPGA (Field-Programmable Gate Array) that has the function of a CPU (Central Processing Unit) and the function of memory such as ROM (Read Only Memory) and RAM (Random Access Memory). It is responsible for synthesizing the image signals acquired from each imaging means (11a to 11f) to create a single composite image. The created composite image is output to the display device 24.

[0028] (4-2) Imaging Unit Control The imaging unit control unit 22, which constitutes the imaging unit control unit 2 of the present invention, is responsible for controlling the rotation angle (θ) of the plane mirror 13, the distance (L) between the imaging means 11 and the plane mirror 13, and the up, down, left, and right movement of the imaging unit holding unit 12 by the imaging unit drive unit 14.

[0029] (4-3) Information Storage Unit The information storage unit 23, which constitutes the imaging control unit 2 of the present invention, includes ROM (Read Only Memory) and RAM (Random Access Memory). It stores various programs executed by the image synthesis unit 21 and the imaging unit control unit 22, as well as information necessary for the execution of these programs. The various programs and information stored in ROM are loaded into RAM and executed.

[0030] 5. Communication Means The communication means 3 of the present invention is responsible for transmitting multiple image signals acquired by each of the multiple imaging units (10a to 11f) to the image synthesis unit 21. It also has the function of controlling the operation of the imaging means 11, such as the timing of imaging, via a general-purpose communication interface such as Camera Link, USB (Universal Serial Bus), CXP (CoaXPress®), or Gigabit Ethernet (GigE).

[0031] 6. Composite Images Figures 4(a) to 4(c) are photographs showing composite images (annular member) captured by the multi-plane imaging system 100 of the present invention and combined by the image synthesis unit 21. In each case, images of the inner and outer surfaces of the annular member captured by the six imaging means from multiple directions are combined into a single image. Figures 5(a) to 5(c) are photographs showing composite images (top-opening container) captured by the multi-plane imaging system 100 of the present invention and combined by the image synthesis unit 21. In each case, images of the inner and outer surfaces of the top-opening container captured by the six imaging means from multiple directions are combined into a single image.

[0032] B. Visual Inspection System Using a Multi-Facing System 1. Diagram 6 of the Visual Inspection System Using a Multi-Facing System illustrates the configuration of a visual inspection system employing the multi-facing imaging system of the present invention (hereinafter referred to as the "multi-facing visual inspection system"). The multi-facing visual inspection system 200 of the present invention consists of an inspection unit 4 in which a plurality of imaging units 10 are arranged spaced apart around the object to be inspected W, an inspection control unit 5, and a communication means 3 connecting the inspection unit 4 and the inspection control unit 5. The multi-facing visual inspection system 200 uses the imaging unit 1 of the multi-facing imaging system 100 described above as the inspection unit 4, and its configuration is identical to the imaging unit 1 of the multi-facing imaging system 100 described above, except that it is equipped with a transport means 6 for transporting the object to be inspected (object to be imaged) W. The multi-facing visual inspection system 200 is characterized by the fact that by using the imaging unit 1 of the multi-facing imaging system 100 as the inspection unit 4, the object to be inspected W can be inspected simultaneously from multiple viewpoints. The inspection unit 4 includes an illumination means 15 for illuminating the object to be inspected W, a plurality of imaging units 10 arranged spaced apart to surround the object to be imaged W at a predetermined distance from the center line of the object to be inspected W, and a transport means 6 for transporting the object to be inspected W. The inspection control unit 5 includes an imaging unit control unit 22 for controlling the imaging units 10, an image synthesis unit 21 for combining and displaying a plurality of inspection image signals acquired by each of the plurality of imaging units (10a to 10f) as a composite image, an image processing unit 26 for image processing of the composite image synthesized by the image synthesis unit 21, a determination unit 27 for determining the quality of the appearance of the object to be inspected W based on the inspection image created by the image processing unit 26, an information storage unit 23, an image storage unit 28, and a transport control unit 29. The configurations of the object to be inspected W, the inspection unit 4, and the communication means 3 are the same as those of the object to be imaged W and the imaging unit 1 described above, so their explanation will be omitted, and the inspection control unit 5 will be described below.

[0033] 2. Inspection Control Unit The inspection control unit 5 that constitutes the multi-face appearance inspection system 200 of the present invention comprises an imaging unit control unit 22 that controls the imaging unit 10, an image synthesis unit 21 that synthesizes and displays multiple inspection image signals acquired by each of the multiple imaging units (10a to 10f) as a composite image, an image processing unit 26 that processes the composite image synthesized by the image synthesis unit 21, a determination unit 27 that determines whether the appearance of the object to be inspected W is good or bad based on the inspection image created by the image processing unit 26, an information storage unit 23, an image storage unit 28, and a transport control unit 29, and may also be provided with various input / output interfaces such as a display device 24 and an input device 25.

[0034] (2-1) Image Synthesis Unit The image synthesis unit 21, which constitutes the inspection control unit 5 of the present invention, is made up of a board equipped with an FPGA (Field-Programmable Gate Array) that has the function of a CPU (Central Processing Unit) and the function of memory such as ROM (Read Only Memory) and RAM (Random Access Memory). It is responsible for synthesizing the image signals acquired from each imaging means (11a to 11f) to create a single composite image. The created composite image is output to the display device 24.

[0035] (2-2) Imaging Unit Control The imaging unit control unit 22, which constitutes the inspection control unit 5 of the present invention, is responsible for controlling the rotation angle (θ) of the plane mirror 13, the distance (L) between the imaging means 11 and the plane mirror 13, and the up, down, left, and right movement of the imaging unit holding unit 12 by the imaging unit drive unit 14.

[0036] (2-3) Information Storage Unit The information storage unit 23, which constitutes the inspection control unit 5 of the present invention, includes ROM (Read Only Memory) and RAM (Random Access Memory). It stores various programs executed by the image synthesis unit 21, the imaging unit control unit 22, and the transport control unit 29, as well as information necessary for the execution of these programs. The various programs and information stored in ROM are loaded into RAM and executed.

[0037] (2-4) Image Processing Unit The image processing unit 26, which constitutes the inspection control unit 5 of the present invention, is responsible for performing various image processing operations on the image information from the image synthesis unit 21 to create an inspection image.

[0038] (2-5) Image Storage Unit The image storage unit 28, which constitutes the inspection control unit 5 of the present invention, includes ROM (Read Only Memory) and RAM (Random Access Memory). The ROM stores various programs such as inspection method programs executed by the CPU, and information necessary for the execution of these programs. The various programs and information stored in the ROM are loaded into the RAM and executed.

[0039] (2-6) Determination Unit The determination unit 27, which constitutes the inspection control unit 5 of the present invention, is responsible for determining whether the appearance of the inner and outer surfaces of the object to be inspected W is good or bad. Specifically, it determines whether the inspection image is good or bad by comparing it with a reference image stored in the image storage unit 28.

[0040] (2-7) Transport Control Unit The transport control unit 29, which constitutes the inspection control unit 5 of the present invention, controls the transport means 6 that transports the objects to be inspected W at equal intervals. The objects to be inspected W are inspected on the transport means 6 in the inspection unit 4. The objects to be inspected W that have been inspected are transported by the transport means 6.

[0041] C. Multi-faceted visual inspection method Figure 7 is a flowchart illustrating the inspection flow of the multi-faceted visual inspection system 200 of the present invention. Figure 8 is a cross-sectional view (A-A') illustrating an inspection mode of the multi-faceted visual inspection system 200 of the present invention. The multi-faceted visual inspection system 200 of the present invention performs a visual inspection of the object to be inspected W in the following procedure.

[0042] 1. Setting Inspection Conditions Based on the characteristics of the object to be inspected W (e.g., container, annular member, height, width), the arrangement of the illumination means 15 and the imaging unit 10, as well as the height of the imaging means 11 and the rotation angle (θ) of the plane mirror 13 are set (S11). Specifically, the arrangement of the illumination means 15 is selected to make the illumination light irradiated onto the object to be inspected W appropriate, and the height of the imaging means 11 and the rotation angle (θ) of the plane mirror 13 are adjusted by the imaging unit drive unit 14 so that the imaging means 11 can appropriately receive reflected light from the inspection position of the object to be inspected W.

[0043] 2. Inspection Image Synthesis The inspection image synthesis unit 21 synthesizes the image signals acquired from each imaging means (11a to 11f) to create a single inspection image (S12).

[0044] 3. Image Processing The image processing unit 26 performs image processing for the image synthesis unit 21 to determine a single inspection image. The image processing is performed in the order of plane image extraction (S13), preprocessing (S14), feature extraction (S15), postprocessing (S16), and blob analysis (S17).

[0045] (3-1) Plane Image Extraction The plane image extraction process (S13) is a process of extracting any one of the tones (composed of red, green, blue, hue, saturation, lightness (L), lightness (V)) of the inspection image. For example, there is a process of extracting the red (R) plane from an RGB image. The mode of the plane image extraction process (S13) can be appropriately selected according to the mode of the inspection image.

[0046] (3-2) Preprocessing The preprocessing (S14) is a process for improving the accuracy of the feature quantity extraction process (S15). Specifically, position correction, image calculation, LUT correction, luminance correction, blurring processing, etc. are appropriately selected and performed according to the mode of the plane-extracted image.

[0047] (3-3) Feature Quantity Extraction The feature quantity extraction process (S15) is a process of extracting characteristic lines and density boundary regions from the plane image. Specifically, the region of interest (ROI), MASK processing, reference difference, binarization, and optical character recognition (OCR) analysis are appropriately selected and performed.

[0048] (3-4) Postprocessing The postprocessing (S16) is a process for improving the accuracy of the blob analysis process (S17). Specifically, hole filling, feature connection, feature calculation, and noise removal are appropriately selected and performed according to the mode of the feature-extracted image.

[0049] (3-5) Blob Analysis The blob analysis process (S17) is an analysis process performed to provide the postprocessed inspection image for inspection image determination (S18). Specifically, shape feature analysis, character string analysis, and distance analysis are appropriately selected and performed according to the mode of the postprocessed image.

[0050] 4. The inspection image determination unit 27 compares the inspection image with a reference image to determine whether the appearance of the object W to be inspected is good or bad (S18). The determination result is output to the display device 24.

[0051] The present invention makes it possible to provide circumferential inspection and multi-face inspection that require multiple imaging means.

[0052] 100 Multi-face imaging system 200 Multi-face appearance inspection system W Object to be imaged, object to be inspected 1 Imaging unit 2 Imaging control unit 3 Communication means 4 Inspection unit 5 Inspection control unit 6 Transport means 7 Half mirror 10 Imaging unit 11 Imaging means 12 Imaging unit holding unit 13 Planar mirror 14 Imaging unit drive unit 15 Illumination means 16 Object to be imaged holding unit 17 Object to be imaged lifting unit 21 Image synthesis unit 22 Imaging unit control unit 23 Information storage unit 24 Display device 25 Input device 26 Image processing unit 27 Judgment unit 28 Image storage unit 29 Transport control unit

Claims

1. A multi-plane imaging system comprising: an imaging unit comprising illumination means for illuminating an object to be imaged and a plurality of imaging units arranged spaced apart around the object to be imaged; an imaging unit control unit for controlling the imaging units; an imaging unit control unit comprising an image synthesis unit for synthesizing a plurality of image signals from the object to be imaged acquired by the plurality of imaging units to create a single composite image; and communication means for connecting the imaging unit and the imaging unit control unit, wherein the imaging unit comprises imaging means, a plane mirror arranged on the optical axis of the imaging means and rotatable with respect to the optical axis, and an imaging means holding unit for holding the imaging means and the plane mirror.

2. The multi-plane imaging system according to claim 1, characterized in that the imaging unit can be independently and individually moved up, down, left, and right by the imaging unit control unit.

3. The multi-plane imaging system according to either claim 1 or 2, characterized in that the illumination means is either surface illumination or pseudo-coaxial incident illumination, either alone or in combination.

4. A multi-faceted visual inspection system comprising: an inspection unit comprising: illumination means for illuminating an object to be inspected; transport means for transporting the object to be inspected; and a plurality of imaging units arranged spaced apart around the object to be inspected; an imaging unit control unit for controlling the imaging units; an image synthesis unit for synthesizing a plurality of image signals from the object to be inspected acquired by the plurality of imaging units to create a single composite image; an inspection control unit comprising: an image processing unit for image processing the composite image created by the image synthesis unit; and a determination unit for determining the inspection image processed by the image processing unit; and communication means for connecting the inspection unit and the inspection control unit, wherein the imaging unit comprises: an imaging means; a plane mirror arranged on the optical axis of the imaging means and rotatable with respect to the optical axis; and an imaging means holding unit for holding the imaging means and the plane mirror.

5. The multi-faceted visual inspection system according to claim 4, characterized in that the imaging unit can be independently and individually moved up, down, left, and right by the imaging unit control unit.

6. The multi-faceted visual inspection system according to either 4 or 5, characterized in that the illumination means is either surface illumination or pseudo-coaxial incident illumination, either alone or in combination.

7. An appearance inspection method using a multi-face appearance inspection system as described in claim 4 or claim 5, comprising: an imaging condition setting step of setting the arrangement of illumination means and the vertical position of each of the plurality of imaging units, the angle and position of the plane mirror, and the optical path length between the imaging means and the plane mirror, based on the characteristics of the object to be inspected, using an imaging unit control unit; an inspection image synthesis step of receiving reflected light from the object to be inspected and synthesizing a plurality of image signals acquired by the plurality of imaging units to create an inspection image; a plane image extraction step of creating a plane image from the inspection image synthesized in the inspection image synthesis step; a pre-processing step of correcting the plane image; a feature extraction step of extracting features from the corrected plane image; a post-processing step of correcting the feature-extracted inspection image; a blob analysis step of performing blob analysis on the corrected inspection image; and an inspection image determination step of determining whether the inspection image is pass or fail based on the inspection image analyzed by blob analysis.

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