JP7030764B2 - Target inspection equipment and methods from multiple viewpoints - Google Patents

Description

The present invention relates to investigating and analyzing an object by the use of optical means, and more particularly to an apparatus for inspecting an object from multiple perspectives with optical means and methods for that purpose.

Visual superficial inspections are commonly used for quality control, data acquisition, and data analysis. This is an important commercial function and can be used, for example, to visually distinguish between damaged and undamaged products from the product / manufacturing / assembly process of the 3C industry.

The traditional approach is to analyze the product sample surface by surface, which can take a long time after all. In any manufacturing process, only a small number of samples are inspected under conditions of constant throughput rate. In other words, some 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 device is disclosed in US Patent Application Publication No. 2008/02393301 for performing a visual inspection of an object from multiple perspectives, which is an observation optical system, a first mirror, and two. I am using a second mirror. By rotating the first mirror while moving it integrally with the observation optical system, observation of the side surface of the object, such as a wafer, is made. Further, top and bottom views can be obtained by moving and rotating the first mirror and the two second mirrors integrally with the observation optical system. Therefore, the duration of the inspection cycle time must be set long enough to allow the completion of mirror repositioning for multi-view inspection, which reduces the inspection rate.

Therefore, an object of the present invention is at least two reflections arranged to simultaneously reflect at least two different side views of an image capture device, an inspection site, and an object positioned at the inspection site to the image capture device. To provide a multi-viewpoint subject inspection device, including the device, where the image capture device has a range of views including at least two different side views of the reflection.

According to another aspect of the invention, it reflects at least two different side views of the subject at the same time, captures an image of at least two different side views of the reflection, captures a flawless view of the subject. Provided is a method of subject inspection, which comprises comparing the image obtained with that of the subject being inspected.
By introducing a reflector into the 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, camera. And / or the object can be inspected at one time in one image frame without the need to reposition. There are more than one reflector placed within the range of the camera's view to assist the inspection process by utilizing the hidden surface of any given solid object that is not the device. The effort to inspect each single part from multiple aspects is reduced. Therefore, the duration of the inspection cycle time can be reduced and inspection to multiple surface levels makes it possible to improve the quality as a whole.

Preferably, at least two reflectors are arranged to guide the light directly from the object, and each of the two reflectors receives a side view of the object directly reflected from the image capture device. It is tilted at a predetermined angle with respect to the optical axis of the image capture device. Such an arrangement of viewing angles allows the reflector to be placed linearly in the field of view of the image capture device. Therefore, it provides an economical solution without the use of extra reflectors.

At least two reflectors are arranged so that the image capture device simultaneously reflects against the top view of the subject's image capture device positioned at the inspection site so that the image capture device receives the top view of the subject directly reflected from it. Is preferable. Thus, the range of the reflector's view can be stretched to cover the top view of the subject, and the controller can perform a comparison of the parts related to the top view of the subject that appear in the images for the top and side views. .. This is advantageous because the light hitting the surface from one side can reveal only a certain set of defects. When provided through a mirror, the light does not hit the surface in one direction, but at at least another angle. One of these different views and the same surface can be seen in the mirror, leading to a more complete examination in only one image frame.

In addition, static scenes in the image frame can be easily masked, so only areas of interest are analyzed.

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

Preferably, the multi-view subject inspection device makes the first surface for supporting the object located at the inspection site and the bottom view of the object at the inspection site the first of at least two reflectors. Further comprising a refracting device having a second surface having an angle away from the first surface, arranged to refract with respect, where the first reflecting device is the refracted bottom surface of the object. It 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 used both for the mechanical support of the subject and for deflecting its bottom view to one of the reflectors. , This compatibility can be enhanced. In addition, one of the reflectors is also used to reflect the bottom view of the subject to the image capture device in addition to the side and / or top views of the subject, which further reduces costs and is often used. Improve compatibility of target inspection equipment from the viewpoint.

The multi-view object inspection device preferably further includes a processor adapted to compare the captured image of the defect-free view of the object with that of the object being inspected. Both the template image and the image for the object to be inspected are affected by the same level of distortion, so the negative effects of distortion are compensated and therefore the identification results are accurate. Surface analysis can be performed using either template-based or machine learning-based algorithms. Any kind of calibration is not needed in any case as the differences from the good parts are investigated. Images from the good parts that serve as templates or as a basis for learning procedures are later acquired in the actual inspection process using exactly the same mechanism.

The subject matter of the present invention will be described in more detail in the following documents with reference to preferred exemplary embodiments described in the drawings.

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

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

In the following description, in order to provide a complete understanding of the present invention, specific details such as specific circuits, circuit components, interfaces, techniques, etc. are disclosed for the purpose of description, but not limitation. .. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments that deviate from these specific details. In another example, well-known methods and detailed descriptions of programming procedures, devices, and circuits are omitted so as not to obscure the description of the present invention with unnecessary details.

1A and 1B respectively show a multi-viewpoint object inspection apparatus according to an embodiment of the present invention, and a cross-sectional view thereof is taken along lines AA of FIG. 1A. As shown in FIGS. 1A and 1B, the multi-viewpoint subject inspection device 1 includes an image capture device 10, an inspection site 11, and at least two reflection devices 12. The image capture device 10 can 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 therefore has a range of fields of view that covers a portion of the field that is visible through the image capture device 10 while the view of the article outside the range of the field of view (FOV) is not visible. The reflecting device 12 can be a mirror for guiding the light from the object to the image capturing device 10. The mirror can be selected as a plane mirror, a concave mirror, or a convex mirror. It is preferable to use a plane mirror as the reflecting device 12. The parallel beam of light changes its direction as a whole, while still keeping its direction parallel. The image formed by the plane mirror is a virtual image of the same dimensions as the original object.

Depending on the requirements of how many side views of the object will be inspected, the number of reflectors can be selected from 2 to 4 as long as more than 1 is counted for multi-view observation purposes. Can be done. In this embodiment according to FIGS. 1A and 1B, at least two reflecting devices 12 are such that at least two different side views of the object positioned at the inspection site 11 are simultaneously reflected against the image capturing device 10. used. For example, the four side views of interest are provided simultaneously to the camera 10 for use with the four mirrors 12 along with the optical paths 13 corresponding to the four side views. The image capture device 10 has a range of fields of view that includes at least two different side views of the reflection. In this example, when the side view is reflected by the mirror 12 and passes through the inspection site 11, the images of the four side views of interest are captured by the camera 10, which is a side view in which the range of the view of the camera 10 is reflected. 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 interest extend to the camera 10. To reach. This makes it possible to distinguish between the outlines of different images corresponding to different side views from the camera's point of view.

By introducing a reflector to the inspection device to allow the camera to "see" parts from multiple views at once, multiple surfaces can be reflected, camera and / or subject in one image frame. Can be inspected at once without the need to reposition for each single surface. More than one reflector placed within the range of the camera's view to assist the inspection process by utilizing the surface that would otherwise be hidden by any given solid object. be. The effort to inspect all single parts from multiple aspects is reduced. Therefore, the duration of the inspection cycle time can be reduced while ensuring high quality complete simultaneous multi-surface inspection.

As shown in FIG. 1B, the 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. With respect to the OA, the reflective surface of the reflector 12 can be positioned facing the image capture device 10 because it is tilted at a predetermined tilt angle α, so that the range 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 subject directly from the reflection device 12. For example, if the plane of the mirror 12 can be positioned to be tilted outward by 30 degrees with respect to the optical axis of the camera 10, the side view of the subject is observed by the camera 10 in the optical path 13 passing through the inspection site 11. Can be done. Such a setting of the viewing angle allows the reflector to be placed linearly in the field of view 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.

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

As described in the section above, the multi-viewpoint subject inspection device 1 may observe more than one side view of the subject at a time, leaving the top view unattended. To simultaneously inspect the top surface of the subject, at least two reflectors 12 may be placed around the inspection site 11, and the range of the field of view of the image capture device 10 further extends the top view of the subject positioned at the inspection site. include. For example, as shown in FIG. 1B, when the mirror 12 is placed so as to surround the inspection site 11 at an inclination angle α that allows its reflective surface facing the camera 10, it starts from the subject and the top surface of the camera 10. There are no articles that interfere with the optical path. Further, since the range of the field of view of the camera 10 has an operable coverage of the mirror 12 surrounding the examination site 11 on which the subject should be placed, this must also cover the top view of the subject. Again, due to this 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 an object that would otherwise be acquired by the device for side view, the operable range of the field of view of the image capture device is utilized to its full extent for multi-view simultaneous inspection. Can be done. Therefore, there is no need for an additional camera to image the top view, nor is there a need for a mechanism to reposition the camera to direct its field of view to the top view of interest.

2A and 2B show a multi-viewpoint subject inspection apparatus according to another embodiment of the present invention and a cross-sectional view thereof taken along line BB of FIG. 2A, respectively. The embodiments according to FIGS. 2A and 2B are substantially similar to those according to FIGS. 1A and 1B, except that FIG. 2 further includes a refracting device 20. To avoid duplication, the description of those common parts is omitted here. The same reference symbol indicates the same part. As shown in FIGS. 2A and 2B, the multi-viewpoint object inspection device 2 has a refraction device 20 having a function of supporting the object. The refracting device 20 reflects the first surface 200 for supporting the object positioned at the inspection site 11 and the bottom surface of the object at the inspection site 11 on the first of at least two reflecting devices 12. It has a second surface 201 that deviates from the first surface 200 having a deflection angle β arranged in. For example, the refracting device 20 can be a deflection prism made of a transparent material with predetermined mechanical strength, such as glass, plastic and fluorite. If the deflection prism 20 is fixed at the inspection site 11 and its first surface 200 mechanically supports the bottom surface of the object at the inspection site 11, the object is therefore mounted on the first surface 200 of the deflection prism 20. Can be. The deflection angle β between the first surface 200 and the second surface 201 is such that the light beam from the bottom surface of the object enters the refraction prism 20 and then by the second surface 201 into one of the mirrors 12. It can be predetermined, for example, to be refracted from the mirror 12 to the left of the inspection site 11 (first reflector). The first reflector 12 may receive the refracted bottom view of the subject and reflect what has been received for the image capture device 10. In such an arrangement, the refracting device provides integrated functions including supporting the object and directing its bottom view towards the image capture device for multi-view simultaneous 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. Be placed. The overlap of the side and bottom views in the image is physical because the edge of the object between these two views blocks the light reflection from the bottom of the object so that it hits the virtual image of the side view of the reflector. Is impossible. Since one of the reflecting devices is also used to reflect the bottom view of the object to the image capturing device, the cost can be reduced for the multi-viewpoint inspection device according to the present invention.
The control device can be used for scratch identification (not shown in the drawings). It can be used to compare a captured image of a defect-free view of an 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 reflector with respect to the optical axis of the image capture device and the deflection angle β between the first and second surfaces of the refractor. The distortion of the image acquired by the image capture device 10 can be derived. The control device may instruct the image capture device 10 to acquire different view images of the intact object as templates and store them in memory as templates. The controller may further compare the template with the image of the view of interest to be inspected to determine if the latter is damaged. Since both the template image and the image about the object to be inspected are affected by the same level of distortion, the negative effects of distortion can be compensated and therefore the identification results are accurate. Surface analysis can be performed using either template-based or machine learning-based algorithms. No calibration of any kind is required as differences from the parts of the goods are investigated in any case. Images from the part of the item that serves as the basis for the template or learning procedure will later be obtained using the exact same setup in the actual inspection process.

For example, FIGS. 3A, 3B, 3C and 3D are an image of the side view of the object as a template, an image of the side view of the object as a template acquired by the image acquisition device, and an inspection acquired by the image acquisition device, respectively. An image of a side view of an unblemished object, showing a damaged object. As shown in FIG. 3A, the outer shape 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 in FIG. 3B, the image of the intact subject side view in FIG. 3C, and the image of the scratched subject side view in FIG. 3D are all. Looks like a trapezoid. The templates shown in FIGS. 3B and 3C and the images for the non-scratched one show no more similar defects to each other, while some defects such as dots and scratches are scratched according to FIG. 3D. Appears in the image of the attached one. Therefore, the controller may use a template-based algorithm to determine whether the subject under examination has defects, despite the effects of distortion induced by the reflections of the side view. One of ordinary skill in the art should understand that a template-based algorithm can be applied to defect detection for the bottom surface of interest, as its bottom view can be reflected to the image capture device according to the solution described above.

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

Alternatively, the image capture device 10 may be positioned to simultaneously reflect the top view of the object positioned at the examination site with respect to the image capture device 10. The top view can be received directly from it. Therefore, the view range of the reflector can be effectively stretched to cover the top view of the subject. For example, as shown in FIGS. 1A and 1B, the top surface marked with a cross at the corner can be seen in the image for the top view and the side view with respect to the image capture device 10. The controller can make a comparison about the parts of the image that appear in the top view and the side view that are related to the top view of the object. This is advantageous because the light from one side to the surface reveals only a certain set of defects. Since the mirror is provided throughout, the light hits the surface not only in one direction, but at least at another angle. One same surface can be seen in the mirrors of these different views, and only one image frame leads to a more complete investigation. In addition, static scenes can easily be covered in the image frame, so only areas of interest are analyzed. Further, the reflector 12 may be arranged so that the lengths of the optical paths 13 of the light are substantially the same to ensure comparable focus on the image captured from the top view of the object of reflection. ..

Although the invention has been described on the basis of some preferred embodiments, one of ordinary skill in the art should be aware that those embodiments do not limit the scope of the invention. Any modifications and modifications to embodiments without departing from the spirit and concept of the invention are within the common wisdom and recognition of those skilled in the art and thus the scope of the invention as defined by the accompanying claims. Should be in.
Below, the matters described in the claims at the time of filing are added as they are.
[1] This is a multi-viewpoint target inspection device.
Image capture device and
Inspection site and
The image capture device includes at least two reflectors arranged to simultaneously reflect at least two different side views of the object located at the inspection site.
The image capture device is a multi-viewpoint object inspection device having a range of views including at least two different side views of the reflection.
[2] The at least two reflectors are arranged to guide light directly from the object, and each of the two reflectors provides a side view of the object to which the image capture device is directly reflected. The multi-viewpoint object inspection device according to [1], which is tilted at a predetermined angle with respect to the optical axis of the image capture device so as to be accepted.
[3] The at least two reflecting devices are positioned at the inspection site so that the image capturing device receives the top view of the object directly reflected from the top view of the object. The multi-viewpoint object inspection device according to [2], which is arranged to reflect simultaneously with respect to the object.
[4] In [2] or [3], the lengths of the optical paths of the light are substantially the same to ensure the same degree of focus for the image captured from the view of the reflection. The multi-viewpoint target inspection device described.
[5] The at least two reflectors are arranged around the inspection site.
The multi-viewpoint subject inspection apparatus according to any one of [1] to [4], wherein the view range of the image capture apparatus further includes a top view of the object positioned at the inspection site.
[6] A first surface for supporting the object positioned at the inspection site and a bottom view of the object at the inspection site are refracted with respect to the first of the at least two reflecting devices. Further comprising a refracting device having a second surface having an angle away from the first surface, arranged so as to.
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 object to the image capturing device. Target inspection equipment by.
[7] The angle between the first surface and the second surface of the refracting device is such that the view range of the first reflecting device includes the side view and the bottom view of the object of the reflection. The multi-viewpoint target inspection device according to [6], which is arranged in.
[8] In any one of [1] to [7], further including a processor adapted to compare the captured image of the view of the defect-free object with that of the object under inspection. The multi-viewpoint target inspection device described.
[9] This is a method of inspecting an object.
Reflecting at least two different side views of the object at the same time,
Capturing images of said at least two different side views of said reflection,
A method comprising comparing the captured image of the side view of a defect-free object with that of the object being inspected.
[10] Reflecting the top view of the object and
9. The method of [9], further comprising capturing an image of the top view of the reflection.
[11] Light is guided directly from the object and is guided.
The method according to [9] or [10], wherein the lengths of the optical paths of the light are substantially the same to ensure the same degree of focus for the image captured from the view of reflection. ..
[12] Refracting the bottom view of the object and
Reflecting the refracted bottom view of the object and
Capturing an image of the refracted bottom view of the subject,
The method according to any one of [9] to [11], further comprising comparing the captured image of the bottom view of the subject without defects with that of the subject being inspected.

Claims (6)

This is a multi-viewpoint target inspection device (1) .
Image capture device (10) and
Inspection site (11) and
The image capture device (10) includes at least two reflectors (12) arranged to simultaneously reflect at least two different side views of the object located at the inspection site (11) .
The image capture device (10) has a range of views including at least two different side views of the reflection.
The object inspection device (1) has a first surface for supporting an object positioned at the inspection site ( 11) and a bottom view of the object at the inspection site (11) at least two reflection devices ( 1). A second prism (20) arranged to guide the first reflecting device (12) of the 12) and having an angle (β) away from the first surface. Further including a prism (20) having a surface and.
The first reflecting device (12) receives the bottom view of the object and reflects the received bottom view to the image capturing device (10) .
The angle (β) between the first surface and the second surface of the prism (20) is in front of the side view of the object in the range of the view of the first reflector (12) . A multi-viewpoint target inspection device (1) arranged so as to include the bottom view without overlapping . The at least two reflectors (12) are arranged to guide the light from the object.
Each of the two reflecting devices (12) relates to the optical axis of the image capturing device (10) so that the image capturing device (10) receives a side view of the object reflected from the target. The multi-viewpoint target inspection device (1) according to claim 1, which is tilted at a predetermined angle (α ). The at least two reflecting devices (12) are arranged so that the image capturing device (10) simultaneously receives the top view and the side view of the object reflected from the object. The multi-viewpoint target inspection device (1) according to Item 2. The multi-viewpoint according to claim 2 or 3, wherein the length of the optical path (13) corresponding to the side view is substantially the same for the image of the side view to ensure the same degree of focus. Target inspection device (1) . The at least two reflectors (12) are arranged around the inspection site (11) .
The multi-viewpoint subject according to any one of claims 1 to 4, wherein the view range of the image capture device (10) further includes a top view of the object positioned at the inspection site (11) . Inspection device (1) . The multi-viewpoint subject according to any one of claims 1-5, further comprising a processor adapted to compare the captured image of the defect-free view of the subject with the image of said subject under examination. Inspection device (1) .

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