JP2020064066A - Object inspection apparatus with multi-viewpoint and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target inspection device from a multi-viewpoint and a method for the same. An object inspection device 1 includes at least two reflecting devices 12 arranged to simultaneously reflect at least two different side views of an object positioned at an inspection site 11 with respect to an image capturing device 10. The image capture device has a range of views that includes at least two different side views of reflections. By introducing a reflector into the subject inspection device to allow the image capture device to see parts from multiple views at once, multiple surfaces can be reflected for each single surface, the image capture device. And / or the object can be inspected at once in one image frame without the need to reposition. [Selection diagram] FIG. 1B

Description

  The present invention relates to investigating and analyzing objects by the use of optical means, and more particularly to an apparatus for examining objects from multiple perspectives with optical means and methods therefor.

  Visual superficial inspection is commonly used for quality control, data acquisition, and data analysis. This is an important commercial feature and can be used, for example, to visually distinguish scratched and undamaged products from the product / fabrication / assembly process of the 3C industry.

  The conventional approach is to analyze the product sample surface by surface, which in the long run is long. Only a small number of samples are tested in a given throughput rate in any manufacturing process. In other words, any defective product can be identified as flawless without inspection, reaching the end of the product line. Therefore, the operator must compromise between production rate and product quality rate. For example, a visual surface inspection apparatus is disclosed in U.S. Patent Application Publication No. 2008/0239301 for performing visual inspection of an object from multiple perspectives, which includes a viewing optics system, a first mirror, and two mirrors. It uses a second mirror. By rotating the first mirror, while moving it integrally with the viewing optics, an observation of the side surface of an object such as a wafer is made. Further, the top and bottom views can be obtained by moving and rotating the first mirror and the two second mirrors integrally with the viewing optics. Therefore, the period of the examination cycle time must be set long enough to allow completion of repositioning of the mirror for multi-view examination, which reduces the examination rate.

  Accordingly, it is an object of the invention to provide at least two different side views of an image capture device, an examination site, and at least two different side views of an object positioned at the examination site, the at least two reflections arranged to reflect the image capture device simultaneously. It is to provide a multi-view object inspection device including a device, wherein the image capturing device has a range of views including at least two different side views of the reflection.

According to another aspect of the invention, it is possible to simultaneously reflect at least two different side views of an object, to capture images of at least two different side views of reflection, to capture a view of a defect-free object. There is provided a method of subject inspection comprising comparing the imaged image with that of the subject under examination.
By introducing a reflector into the inspection device to allow the image capture device to "see" portions from multiple views at once, multiple surfaces can be created for each single surface. And / or can be examined in one image pane at a time without having to reposition the object. There are more than one reflectors placed in range of the camera's view to assist the inspection process by utilizing the obscuring surface of any given solid object, if not the present device. The effort of inspecting each single part from multiple sides is reduced. Therefore, the duration of the inspection cycle time can be reduced, and inspection to multiple surface levels allows to improve the quality as a whole.

  Preferably, at least two reflectors are arranged to direct light directly from the object, each of the two reflectors such that the image capture device receives a side view of the object directly reflected therefrom. It is tilted at a predetermined angle with respect to the optical axis of the image capture device. Such an arrangement of viewing angles makes it possible to position the reflector at a direct line of sight of the image capture device. It therefore provides an economical solution without the use of extra reflectors.

  The at least two reflectors are arranged to simultaneously reflect with respect to the image capture device top view of the object positioned in the examination portion so that the image capture device receives the top view of the object directly reflected therefrom. Is preferred. Thus, the range of views of the reflector may be stretched to cover the top view of the object, and the controller may perform a comparison on the portion associated with the top view of the object that appears in the images for the top and side views. . This is advantageous because the light striking the surface from one side can only reveal a certain set of defects. When provided through a mirror, light does not impinge on the surface in one direction, but at at least another angle. The same surface as one of these different views can be seen in the mirror, leading to a more complete investigation in only one image frame.

  Furthermore, static scenes in the image frame can easily be masked so that only the regions of interest are analyzed.

  Preferably, the length of the optical path of the light is substantially the same to ensure a similar degree of focus for the images captured from the view of the object reflected by the at least one reflector.

  Preferably, the multi-view object inspection device provides a first surface for supporting an object positioned at the inspection site and a bottom view of the object at the inspection site to a first of the at least two reflectors. A refracting device having a second surface at an angle away from the first surface, the refracting device being configured to refract relative to the first surface, wherein the first reflecting device is a refracted bottom surface of the object. Accepts the view and reflects what is received to the image capture device. The cost for a multi-view inspection device can be reduced because the refracting device is reused both for the mechanical support of the object and for deflecting its bottom view to one of the reflecting devices. , This compatibility can be enhanced. In addition, one of the reflectors is reused to reflect the object's side view and / or top view as well as the object's bottom view to the image capture device, which further reduces cost and multi-view. Increase the compatibility of the target inspection equipment.

  The multi-view object inspection apparatus preferably further comprises a processor adapted to compare the captured image of the view of the defect-free object with that of the object under inspection. Since both the template image and the image for the object to be inspected are affected by the same level of distortion, the negative effects of distortion are compensated and thus the identification result is accurate. Surface analysis can be performed using either template-based or machine learning-based algorithms. No calibration of any kind is required since in any case the difference from the good part is investigated. The image from the good part, which serves as a template or as a basis for the learning procedure, is later acquired in the actual inspection process using the exact same scheme.

  The subject matter of the invention is explained in more detail in the following documents with reference to the preferred exemplary embodiments illustrated in the drawings.

FIG. 1A illustrates a multi-view object inspection apparatus according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A of the target inspection apparatus from multiple viewpoints according to the embodiment of the present invention. FIG. 2A illustrates a multi-view object inspection apparatus according to another embodiment of the present invention. 2B is a cross-sectional view of the multi-view object inspection apparatus according to another embodiment of the invention, taken along line BB of FIG. 2A. FIG. 3A shows an image of the target side view as a template. FIG. 3B shows an image of the target side view as a template acquired by the image acquisition device. FIG. 3C shows an image of a side view of an intact object under examination acquired by the image acquisition device. FIG. 3D shows an image of a side view of the injured object under examination acquired by the image acquisition device. FIG. 4A shows a top view image of the target as a template acquired by the image acquisition device. FIG. 4B shows an image of a top view of a flaw-free object under examination acquired by the image acquisition device. FIG. 4C shows a top view image of the injured subject under examination acquired by the image acquisition device.

  The reference symbols used in the figures and their meanings are listed in the form of an overview in the list of reference symbols. In principle, identical parts are provided with the same reference symbols in the figures.

  In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular circuits, circuit components, interfaces, techniques, etc., in order to provide a thorough understanding of the present invention. . However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and programming procedures, devices, and circuits have been omitted so as not to obscure the description of the present invention with unnecessary detail.

  1A and B each show a multi-view object inspection apparatus according to an embodiment of the present invention, a cross-sectional view of which is taken along line AA of FIG. 1A. As shown in FIGS. 1A and 1B, a multi-viewpoint target inspection apparatus 1 includes an image capturing apparatus 10, an inspection region 11, and at least two reflecting apparatuses 12. The image capture device 10 may be a camera for receiving light from an object that is inspected and either reflected or refracted through various optical paths. The image capture device 10 thus has a range of field of view that covers the portion of the field that is visible through the image capture device 10, although a view of the article outside the field of view (FOV) is not visible. The reflector 12 may be a mirror for directing light from the object to the image capture device 10. The mirror can be selected as a plane mirror, a concave mirror or a convex mirror. The reflector 12 preferably uses a plane mirror. The collimated beam of light changes its direction as a whole, while still keeping its directions parallel. The image formed by the plane mirror is a virtual image with the same dimensions as the original object.

  Depending on how many side views of the object will be inspected, the number of reflectors can be chosen from 2 to 4 as long as more than one is counted for the purpose of multi-view observation. Can be done. In this embodiment according to FIGS. 1A and 1B, the at least two reflectors 12 are arranged to simultaneously reflect at least two different side views of the object located at the examination site 11 to the image capture device 10. used. For example, four side views of the object are provided simultaneously to the camera 10 to use the four mirrors 12, with optical paths 13 corresponding to the four side views. The image capture device 10 has a range of field of view that includes at least two different side views of reflection. In this example, as the side view is reflected by the mirror 12 and passes through the examination site 11, images of the four side views of the object are captured by the camera 10, which are side views in which the range of view of the camera 10 is reflective. , So that they do not overlap each other in the field of view of the camera 10 as described above, where the optical paths 13 reflected from the four mirrors 12 corresponding to the four side views of the object extend to the camera 10. To reach. This allows to distinguish between different image outlines corresponding to different side views from the camera's point of view.

  By introducing a reflective device into the inspection device to allow the camera to "see" portions from multiple views at once, multiple surfaces can be reflected in a single image frame by the reflective device, the camera and / or the object. Can be inspected at one time without having to reposition each single surface. To assist the inspection process by utilizing the otherwise hidden surface of any given solid object, there may be more than one reflector placed in the range of the camera's view. is there. The effort of inspecting every single part from multiple sides is reduced. Thus, the duration of the inspection cycle time can be reduced while ensuring high quality complete simultaneous multi-surface inspection.

  As shown in FIG. 1B, at least two reflectors 12 are preferably arranged to guide light directly from the object, each of the two reflectors 12 having an optical axis of the image capture device 10. Being tilted at a predetermined tilt angle α with respect to OA, the reflective surface of the reflector 12 can be positioned facing the image capture device 10 and thus the extent of the field of view of the image capture device 10 is operable coverage. , The image capture device 10 may receive the reflected side view of the object directly from the reflection device 12. For example, if the plane of the mirror 12 can be positioned so that it is tilted outward by 30 degrees with respect to the optical axis of the camera 10, then the side view of the object is viewed by the camera 10 in the optical path 13 passing through the examination site 11. Can be done. Such a setting of the viewing angle makes it possible to position the reflector at a direct line of sight of the image capture device. Therefore, it also provides an economical solution without the use of extra reflectors. For example, this approach is cost effective as only one camera with several reflectors is required for multiple view analysis when compared to multiple cameras.

  Furthermore, the reflector 12 ensures that the optical paths 13 of the light are of substantially the same length in order to ensure comparable focus for images captured from at least two different side views of the reflective object. Can be placed. For example, as shown in FIGS. 1A and 1B, each of the four mirrors 12 is placed on one of the side surfaces aligned with the side surface of the bottom surface of the inspection site 11 indicated by reference numeral 120, to allow inspection. The bottom surface of the portion 11 may have a tilt angle α.

  As described in the preceding section, the multi-view object inspection apparatus 1 may observe more than one side view of the object at a time, leaving the top view unattended. In order to simultaneously inspect the upper surface of the object, at least two reflectors 12 may be arranged around the inspection area 11, the extent of the field of view of the image capture device 10 further comprising a top view of the object positioned at the inspection area. Including. For example, as shown in FIG. 1B, if the mirror 12 is placed to surround the examination site 11 at an inclination angle α that allows its reflective surface facing the camera 10, starting from the top surface of the object and the camera 10. There are no objects that interfere with the optical path. Furthermore, since the field of view of the camera 10 has an operable coverage of the mirror 12 surrounding the examination site 11 on which the object is to be placed, this must likewise cover the top view of the object. Again, due to such operable range of the field of view of the image capture device 10, the images acquired from the top and side views of the subject are distinguishable from each other. By capturing an image of the top view of the object that is not otherwise captured in the device for side view, the operational range of the image capture device's field of view is utilized to its full extent for multi-view simultaneous inspection. Can be done. Thus, there is no need for an additional camera to image the top view or a mechanism to reposition the camera to direct its field of view to the top view of the subject.

  2A and 2B respectively show a multi-view object inspection device according to another embodiment of the invention and its cross-sectional view taken along line BB of FIG. 2A. The embodiment according to FIGS. 2A and 2B is substantially similar to that according to FIGS. 1A and 1B, except that FIG. 2 further comprises a refracting device 20. To avoid duplication, a description of their intersection is omitted here. Like reference symbols indicate like parts. As shown in FIGS. 2A and 2B, the multi-viewpoint object inspection apparatus 2 includes a refraction device 20 having a function of supporting an object. The refraction device 20 is adapted to reflect a first surface 200 for supporting an object positioned at the examination site 11 and a bottom surface of the object at the examination site 11 to a first one of the at least two reflecting devices 12. Has a second surface 201 which is offset from the first surface 200 having a deflection angle β. For example, the refraction device 20 can be a deflecting prism made of a transparent material having a predetermined mechanical strength such as glass, plastic and fluorspar. The deflection prism 20 is fixed at the examination site 11 and its first surface 200 mechanically bears the bottom surface of the object at the examination site 11, so that the object is mounted on the first surface 200 of the deflection prism 20. Can be done. The deflection angle β between the first surface 200 and the second surface 201 is such that the light beam from the lower surface of interest enters the refraction prism 20 and then is directed by the second surface 201 to one of the mirrors 12. , Can be pre-determined such that it can be refracted from the mirror 12, for example, to the left of the examination site 11 (first reflector). The first reflecting device 12 may receive a refracted bottom view of the object and reflect that received for the image capture device 10. In such an arrangement, the refractive device provides integrated functionality, including supporting the object and directing its bottom view to the image capture device for simultaneous multi-view inspection.

Preferably, the deflection angle β of the refracting device 20 between the first surface 200 and the second surface 201 is such that the view range of the first reflecting device includes the side view and the bottom view of the object of reflection. Will be placed. The overlap of the side and bottom views in the image is physically because the edge of the object between these two views blocks light reflections from the bottom surface of the object so as to strike the side view virtual image of the reflector. Impossible. The cost can be reduced for a multi-view inspection device according to the invention because one of the reflectors is reused to reflect the target bottom view to the image capture device.
The controller can be used for wound identification (not shown in the drawing). This can be used to compare the captured image of the view of the defect-free object with that of the object under inspection. The reflection of the side view and / or the bottom view of the object is due to the tilt angle α of the reflecting device with respect to the optical axis of the image capture device and the deflection angle β between the first surface and the second surface of the refracting device, It may lead to distortion of the image acquired by the image capture device 10. The controller may instruct the image capture device 10 to take different view images of the intact object as templates and store them as templates in memory. The controller may further compare the template with an image of the view of the subject to be examined to determine if the latter is damaged. Since both the template image and the image of the object to be inspected are affected by the same level of distortion, the negative effects of distortion can be compensated and the identification result is therefore accurate. Surface analysis can be performed using either template-based or machine learning-based algorithms. No calibration of any kind is required as the differences from the item parts are investigated in any case. The image from the part of the article that serves as the basis for the template or learning procedure is later obtained using the exact same setup in the actual inspection process.

  For example, FIGS. 3A, 3B, 3C, and 3D respectively show a side view of an object as a template, an image of a side view of an object as a template acquired by an image acquisition device, an examination acquired by an image acquisition device, respectively. An image of a side view of a non-scratched subject, showing a scratched subject. As shown in FIG. 3A, the profile of the side view of the template is rectangular. In contrast, due to the effects of distortion, the outline for the image of the template of FIG. 3B, the image of the intact object side view of FIG. 3C, and the image of the damaged object side view of FIG. 3D are all It looks like a trapezoid. The images shown in FIGS. 3B and 3C for the template and the scratch-free one do not show defects that are more similar to each other, while some defects, such as spots and scratches, are scratched according to FIG. 3D. Appears in the image of the attached one. Therefore, the controller may determine whether the object under inspection has a defect by using a template-based algorithm despite the effects of side view reflection-induced distortions. Those skilled in the art should understand that the template-based algorithm can be applied to defect detection for the bottom surface of an object, as its bottom view can be reflected to the image capture device according to the solution described above.

  4A, 4B and 4C respectively show an image of a top view of an object, a template acquired by an image acquisition device, an image of a top view of an intact object under inspection acquired by the image acquisition device and a scratch. It is shown as the target one. Since the image capture device is placed facing the top view of the object, no projection distortion is introduced into the image according to FIGS. 4A, 4B and 4C. As shown in FIGS. 4A, 4B, and 4C, the outline for the top view image of the template, the intact top view image, and the scratched top view image are all rectangular in shape. Some defects, such as spots and scratches, are shown according to FIG. 4C, while the images of the template and the scratch-free ones shown in FIGS. 4A and 4B do not show defects that are more similar to each other. Appears in the image of the attached one. Therefore, the controller may use a template-based algorithm to determine whether the object under inspection has a defect.

  Alternatively, the at least two reflectors 12 may be arranged to simultaneously reflect a top view of an object positioned at the examination site with respect to the image capture device 10, so that the image capture device 10 is reflective of the object. The top view can be directly received from it. Thus, the extent of the reflector's view can be effectively stretched to cover the subject's top view. For example, as shown in FIGS. 1A and 1B, the top surface marked with crosses at the corners can be seen in the images for the top and side views for the image capture device 10. The controller may make a comparison regarding the portion associated with the top view of the object that appears in the images for the top and side views. This is advantageous because the light striking the surface from one side reveals only a certain set of defects. Since the mirror is provided in its entirety, the light strikes the surface not only in one direction but at least another angle. One and the same surface can be seen in these different view mirrors, and only one image frame can lead to a more complete investigation. Moreover, in the image frame, static scenes can easily be covered, so only the area of interest is analyzed. Furthermore, the reflector 12 may be arranged such that the optical path 13 of the light is of substantially the same length to ensure a similar focus on the image captured from the top view of the object of reflection. .

  Although the present invention has been described based on some preferred embodiments, those skilled in the art should recognize that those embodiments do not limit the scope of the present invention. Any variation and modification to the embodiments without departing from the spirit and concept of the invention are within the common general knowledge and these recognitions by a person skilled in the art, and therefore the scope of the invention defined by the appended claims. Should be.

Although the present invention has been described based on some preferred embodiments, those skilled in the art should recognize that those embodiments do not limit the scope of the present invention. Any variations and modifications to the embodiments without departing from the spirit and concept of the invention are within the common general knowledge and these recognitions by a person skilled in the art, and therefore the scope of the invention defined by the appended claims. Should be.
Below, the matters described in the claims at the beginning of the application will be added as they are.
[1] A target inspection apparatus from multiple viewpoints,
An image capture device,
Inspection site,
At least two reflectors arranged to simultaneously reflect at least two different lateral views of the object positioned at the examination site with respect to the image capture device;
The multi-view object inspection device, wherein the image capture device has a range of views including at least two different side views of the reflection.
[2] The at least two reflectors are arranged to direct light directly from the object, and each of the two reflectors provides a side view of the object from which the image capture device is directly reflected. The multi-view object inspection device of [1], as received, tilted at a predetermined angle with respect to an optical axis of the image capture device.
[3] The at least two reflectors have a top view of the image capture device of the object positioned at the examination site such that the image capture device receives a top view of the object reflected directly therefrom. The multi-viewpoint target inspection apparatus according to [2], which is arranged to reflect simultaneously with respect to.
[4] The length of the optical path of the light is substantially the same to ensure comparable focus for images captured from the view of the reflection, [2] or [3] Target inspection device from the multiple viewpoints described.
[5] The at least two reflecting devices are arranged around the inspection site,
The multi-view object inspection apparatus according to any one of [1] to [4], wherein the view range of the image capturing apparatus further includes a top view of the object positioned at the inspection region.
[6] Refracting a first surface for supporting the object positioned at the examination site and a bottom view of the object at the examination site with respect to a first one of the at least two reflecting devices. Further comprising a refraction device disposed with a second surface having an angle away from the first surface,
The multi-viewpoint according to any one of [1] to [5], wherein the first reflecting device receives the refracted bottom view of the object and reflects the received one to the image capture device. Target inspection equipment by.
[7] The angle between the first surface and the second surface of the refracting device is such that the extent of the view of the first reflecting device includes the side view and the bottom view of the object of the reflection. The multi-viewpoint target inspection apparatus according to [6], which is disposed in.
[8] The method of any one of [1]-[7], further comprising a processor adapted to compare the captured image of the view of a defect-free object with that of the object under inspection. Target inspection device from the multiple viewpoints described.
[9] A method for inspecting an object, comprising:
Simultaneously reflecting at least two different side views of the object;
Capturing images of the at least two different side views of the reflection;
Comparing the captured image of the side view of a defect-free object with that of the object under inspection.
[10] reflecting a top view of the object;
Capturing an image of the top view of the reflection. [9].
[11] Light is guided directly from the object,
The method of [9] or [10], wherein the optical path lengths of the light are substantially the same to ensure similar focus for images captured from the reflection views. .
[12] refracting a bottom view of the object;
Reflecting the refracted bottom view of the object;
Capturing an image of the refracted bottom view of the object;
The method of any one of [9]-[11], further comprising: comparing the captured image of the bottom view of the object free of defects with that of the object under inspection.

Claims (12)

A target inspection device from multiple viewpoints,
An image capture device,
Inspection site,
At least two reflectors arranged to simultaneously reflect at least two different lateral views of the object positioned at the examination site with respect to the image capture device;
The multi-view object inspection device, wherein the image capture device has a range of views including at least two different side views of the reflection.   The at least two reflectors are arranged to direct light directly from the object, each of the two reflectors such that the image capture device receives a side view of the object directly reflected therefrom. The multi-view object inspection device according to claim 1, wherein the device is tilted at a predetermined angle with respect to the optical axis of the image capturing device.   The at least two reflectors are relative to a top view of the image capture device of the object positioned at the examination site such that the image capture device receives a top view of the object directly reflected therefrom. The multi-view object inspection apparatus according to claim 2, wherein the object inspection apparatus is arranged for simultaneous reflection.   4. The multi-view according to claim 2 or 3, wherein the optical path lengths of the light are substantially the same to ensure comparable focus for images captured from the view of the reflection. Target inspection device. The at least two reflectors are arranged around the examination site,
5. The multi-view object inspection apparatus according to claim 1, wherein the range of views of the image capture device further includes a top view of the object positioned at the inspection site. A first surface for supporting the object positioned at the examination site and a bottom view of the object at the examination site for refracting with respect to a first one of the at least two reflectors. Further comprising a refraction device disposed with a second surface having an angle away from the first surface,
A multi-view object according to any one of claims 1 to 5, wherein a first reflecting device receives the refracted bottom view of the object and reflects the received light to the image capture device. Inspection device.   The angle between the first surface and the second surface of the refracting device is arranged such that the extent of the view of the first reflecting device includes the side view and the bottom view of the object of the reflection. The multi-view target inspection device according to claim 6.   8. The multi-view according to any one of claims 1 to 7, further comprising a processor adapted to compare the captured image of the view of a defect-free object with that of the object under examination. Target inspection device. A method of examining an object,
Simultaneously reflecting at least two different side views of the object;
Capturing images of the at least two different side views of the reflection;
Comparing the captured image of the side view of a defect-free object with that of the object under inspection. Reflecting a top view of the object;
The method of claim 9, further comprising capturing an image of the top view of the reflection. Light is guided directly from the object,
11. The method according to claim 9 or 10, wherein the optical path lengths of the light are substantially the same to ensure similar focus for images captured from the reflection views. Refracting the bottom view of the object;
Reflecting the refracted bottom view of the object;
Capturing an image of the refracted bottom view of the object;
12. The method of any one of claims 9-11, further comprising comparing the captured image of the bottom view of the object free of defects with that of the object under inspection.