JP7338769B1 - inspection equipment - Google Patents

Abstract

[Problem] The present invention corrects the variation in image size due to the detection position on the rotating test table by using an image acquired using an array of image sensors extending in the radial direction of the rotating test table. To provide an inspection device capable of determining the quality of an inspection based on the actual size of the object. The present invention provides an image acquisition unit that acquires an image on a rotating inspection table using an array of image sensors extending in the radial direction of the inspection table, and a detected position of an object captured in the image. and a target object detection unit that detects an imaging size, a resolution determination unit that determines a resolution based on the detected position of the target, and corrects a variation in the imaging size caused by rotation of the inspection table based on the resolution. The present invention also relates to an inspection apparatus including an imaging size correction section that determines the true size of the object, and a quality determination section that determines the quality of the inspection based on the true size. [Selection diagram] Figure 3

Description

The present invention relates to an inspection device.

2. Description of the Related Art As an inspection apparatus for inspecting an object to be inspected by imaging a rotating inspection table, there is an inspection apparatus that images the entire inspection table at once with one camera.

Japanese Patent Application Laid-Open No. 2007-158033

However, in an apparatus having a jig or the like above the table to be inspected, when the entire table to be inspected is imaged by one camera, a blind spot occurs in the imaging range. Therefore, it is possible to use an inspection apparatus or the like that captures an image of the entire inspection table by capturing an image of the rotating inspection table using an imaging device array extending in the radial direction of the inspection table.

On the other hand, in an inspection apparatus using an array of imaging elements extending in the radial direction of the table to be inspected, it is difficult to accurately grasp the size of the object when attempting to determine the quality of the inspection based on the size of the object based on the captured image. There was a problem of difficulty. This is the case where the size detected in the captured image deviates from the size of the actual object depending on whether the position of the inspection object on the table to be inspected is on the inner circumference side or the outer circumference side. This is because there was

Therefore, the present invention corrects the fluctuation of the imaging size due to the detection position on the rotating inspection table even by using the image acquired by using the image pickup device array extending in the radial direction of the rotating inspection table, and corrects the object. To provide an inspection device capable of making a pass/fail judgment based on a size.

According to a first aspect of the present invention, an image acquisition unit acquires an image on a rotating inspection table using an imaging element array extending in a radial direction of the inspection table;
an object detection unit that detects a detection position and an imaging size of an object captured in the image;
a resolution determination unit that determines resolution based on the detected position of the object;
an imaging size correcting unit that corrects the variation of the imaging size caused by the rotation of the table to be inspected based on the resolution and sets the object to the true size;
and a pass/fail judgment unit that judges pass/fail in the inspection based on the true size.

In a second aspect of the present invention, the resolution determining unit calculates the pixel-by-pixel resolution for each pixel line in the circumferential direction of the inspection table,
The inspection according to the first aspect, wherein the imaging size correction unit corrects the imaging size by the pixel-by-pixel resolution, and sets the sum of the corrected imaging sizes for each pixel line as the true size of the object. It is a device.

In a third aspect of the present invention, the resolution determination unit obtains the coordinates of the center of gravity of the object with respect to the center of rotation of the table to be inspected, and determines a representative resolution representing each object based on the coordinates of the center of gravity. death,
The inspection apparatus according to the first aspect, wherein the imaging size correcting unit corrects the imaging size of the object using the representative resolution.

In a fourth aspect of the present invention, the resolution determining unit uses library data for geometrically determining the coordinates of the center of gravity of the object based on the contour shape of the object on the image including the fluctuation of the imaging size. The inspection apparatus according to the third aspect, in which the coordinates of the center of gravity are determined by

A fifth aspect of the present invention is the inspection apparatus according to any one of the first to fourth aspects, wherein the image acquiring section acquires the image by a line camera.

According to the present invention, an image captured by an array of imaging elements extending in the radial direction of a rotating inspection table is used to compensate for variations in image pickup size due to detection positions on the rotating inspection table, thereby determining quality. can do

4 is an illustration of imaging an object in accordance with one aspect of the present disclosure; It is an example of a configuration of a functional unit according to one aspect of the present disclosure. 1 is a schematic diagram of an inspection apparatus according to one aspect of the present disclosure; FIG. It is an example of the procedure of the inspection method in one aspect of the present disclosure. It is an example of resolution determination in the first embodiment. It is an example of resolution determination in the second embodiment.

<Knowledge of the inventor>
In the inspection apparatus 10 using an array of imaging elements extending in the radial direction of the inspection table 110, the size of the object P detected in the captured image may be dissociated from the actual size of the object P. . The reason for this is that the moving speed of the object P captured by the imaging device array varies depending on the existing position of the object P on the rotating inspection table. Regarding this point, in the schematic diagram of FIG. 1, three objects P (P1, P2, P3) having the same actual size are present on the inspection table 110 at different distances from the rotation center Rc. A case will be described as an example. At P1 existing on the inner circumference side of the rotation radius, P2 existing near the center, and P3 existing on the outer circumference side, (1) the difference in the movement distance (peripheral speed) in the circumferential direction causes (2) the imaging element array The amount of movement of the object P per imaging time is different from each other, and (3) the imaging size of the object P detected in the image may vary from the actual size.

Specifically, (1) the objects P1, P2, and P3 are measured at a peripheral speed (velocity in the tangential direction of rotation, movement distance on the circumference per unit time) on the table to be inspected that rotates about the center of rotation Rc. ) are different from each other. The peripheral speed is determined by the diameter (of the rotating body) and the number of revolutions (peripheral speed = π x diameter x number of revolutions), and the larger the diameter, the higher the peripheral speed. For this reason, P1 located on the inner peripheral side has a lower peripheral speed than P2 (the amount of movement in the circumferential direction per unit time is small). On the other hand, P3 located on the outer peripheral side has a higher peripheral speed than P2 (the amount of movement in the circumferential direction is large). Due to this difference in peripheral speed, (2) the amount of movement of the object P per imaging time for capturing and imaging P1, P2, and P3 by the camera 120 differs. Specifically, since P1 has a lower peripheral speed than P2, the amount of movement from the start of imaging to the end of imaging the entire object is longer. On the other hand, since the peripheral speed of P3 is higher than that of P2, the amount of movement of the object P until the end of imaging by the camera 120 is short.

As a result, (3) in the captured image 130 captured by the camera 120, the sizes of P1, P2, and P3 in the image are different from each other. P1 located on the inner circumference side is observed as a large size in the captured image 130 because the amount of movement is longer than P2. On the other hand, P3, which is located on the outer peripheral side, is observed as a smaller size in the captured image 130 because it has a shorter movement amount than P2. In the captured image 130 of FIG. 1, W represents the width direction of the visual field range of the camera 120, and H represents the circumferential direction in the image captured while the table 110 to be inspected is rotated once.

As described above, in the inspection apparatus 10 using the array of imaging elements extending in the radial direction of the table 110 to be inspected, the size of the object P in the captured image may vary from the size of the actual object. . Due to such size fluctuations, it is sometimes difficult to know the actual size of the actual object P on the table to be inspected in order to judge the quality of the inspection according to the actual size of the object P on the inspection table. There was a problem that I couldn't do it.

Based on such findings, the inventors of the present invention have found that, even with an inspection apparatus 10 that uses an array of imaging elements extending in the radial direction of the table 110 to be inspected, quality determination can be made based on the actual size of the object P. The inspection apparatus 10 has been earnestly studied, and the inspection apparatus 10 of the present invention that solves the above problems has been completed.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

<First embodiment>
A first embodiment will be described as one aspect of the present disclosure with reference to the drawings.

(1) Inspection Purpose and Object The inspection apparatus 10 in this embodiment can be used to inspect an object placed on a rotating inspection table 110 . There are no particular restrictions on the type of object to be inspected or the contents of the inspection. For example, the inspection table 110 is a polished surface, and can be used to inspect the presence or absence of damage to an object to be inspected that has been rotated and polished. In this case, after the object to be polished (object to be inspected) is removed from the table 110 to be inspected after being polished, the remaining object on the table 110 to be inspected is imaged as the object P. Then, depending on the existence or non-existence of an object P having a predetermined size or larger, the state of damage due to polishing of the object to be inspected is inspected. The inspection apparatus 10 of the present invention is suitably used when it is desired to perform an inspection based on the actual size of the object P, as in the inspection described above.

(2) Configuration of Inspection Apparatus As shown in FIG. The information processing apparatus 200 may include an object detection section 210 , a resolution determination section 220 , an imaging size correction section 230 and a quality determination section 240 . Note that the inspection apparatus 10 may include components other than these.

The image acquisition unit 100 is configured to acquire an image using an imaging element array extending in the radial direction (radial direction) of the rotating inspection table 110 . For example, as shown in FIG. 3, the camera 120 may be arranged so as to have an array of imaging elements extending in the XY direction, which is the radial direction. As the camera 120, an appropriate type may be applied as long as it can capture an image with a required resolution according to the intended inspection. A line camera may be used as the camera 120 .

The shape of the inspection table 110 is not particularly limited. For example, in addition to the ring shape shown in FIG. 3, any shape such as a disk shape may be used. The image acquisition unit 100 may include one or more illuminators that illuminate the imaging range on the table 110 to be inspected. The light-emitting means for illumination is not particularly limited, and for example, fluorescent lamps, organic or inorganic electroluminescence (EL), light-emitting diodes, and the like can be used.

The target object detection unit 210 is configured to detect the detection position and imaging size of the target object P in the captured image. The object detection unit 210 may be configured by equipping the information processing apparatus 200 with an image processing function, for example. The object P may be arbitrarily set according to the inspection contents targeted by the inspection apparatus 10 . As in the present embodiment, the object P may be an object to be inspected that has been damaged and has become smaller than the original size by a predetermined amount or more.

The resolution determining section 220 is configured to determine the resolution based on the detected position of the object P. FIG. The resolution is also called pixel resolution, and is determined by the size of the field of view per pixel of the image pickup device (resolution (mm/pixel)=field size of captured image (mm)/number of pixels of image pickup device (pixels)). In this embodiment, the resolution is used to correct size variations of the object P that occur between the inner and outer peripheries of the table 110 to be inspected. As described above, the size variation is the dissociation from the actual size caused by the imaging time of the object P being different between the inner circumference side and the outer circumference side on the rotating inspection table 110 . In this embodiment, since the object P is imaged by the array of imaging elements extending in the radial direction XY, the degree of size variation is determined for each pixel line extending in the XY direction. Based on the above, the resolution for each pixel line is determined according to the detection position of the object P, with reference to the pixel lines in the circumferential direction.

The captured image size correction unit 230 is configured to correct the variation of the captured image size to obtain the true size. The captured image size correction unit 230 of the present embodiment corrects the variation of the captured image size for each pixel line based on the pixel-by-pixel resolution _RI determined by the resolution determination unit 220 .

The pass/fail judgment unit 240 is configured to judge pass/fail in inspection based on the true size. The pass/fail of the inspection can be arbitrarily set according to the contents of the target inspection. For example, as in the present embodiment, if there is an object P whose true size is equal to or larger than a predetermined size, it may be determined that the inspection is defective.

The information processing apparatus 200 described above may be configured by combining hardware resources such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). Further, the information processing apparatus 200 may be configured such that, by executing a pre-installed predetermined program (software), information processing by the software is specifically realized using hardware resources. As described above, the information processing apparatus 200 can be configured to control the processing operations in the object detection unit 210 , the resolution determination unit 220 , the imaging size correction unit 230 , and the quality determination unit 240 .

(3) Inspection Method Procedure The inspection method procedure using the inspection apparatus 10 of the present embodiment will be described below with reference to FIG.

In the inspection method of this aspect,
a step of acquiring an image using an array of image elements extending in the radial direction of the table to be inspected (step A);
A step of detecting the detection position and the imaging size of the object imaged in the image (step B);
a step of determining the resolution based on the detected position of the object (step C);
a step (step D) of correcting, based on the resolution, the amount of fluctuation in the imaging size caused by the rotation of the table to be inspected;
and a step (step E) of judging the pass/fail in the inspection based on the true size.

Step of acquiring an image (Step A)
In process A, an image on the rotating inspection table 110 is acquired using an imaging device array extending in the radial direction of the inspection table 110 . By capturing an image while the table 110 to be inspected rotates once, it is possible to obtain an image of the entire table to be inspected 110 as an imaging range. An image may be obtained on the table 110 to be inspected when obtaining the image in a state corresponding to the target inspection content. As in this embodiment, after removing the polished inspection object on the inspection table 110, the object P remaining on the inspection table 110 may be imaged.

In step A, it is preferable to acquire the image so that the object P can be detected in the binarized image and image processing can be facilitated. For example, it is preferable to maintain uniform brightness by lighting within the imaging range of the imaging element array. Moreover, when the color of the object P is known in advance, it is also preferable to adopt the table 110 to be inspected that has a surface color that can be easily distinguished from the object P when binarized.

Step of detecting an object (step B)
In step B, the object detection unit 210 detects the detection position and the imaging size of the imaged object P in the image acquired in step A. FIG. At the time of detection, the image obtained in step A is binarized so that the part where the object P exists and the other parts can be distinguished, and then the position and imaging size of the part where the object P exists is preferably detected. It is preferable to detect the detection position and the imaging size for each target P. The detected position may be output in any format that can be used by the resolution determining section 220, which will be described later. For example, the detected position may be output as coordinates based on the position relative to the rotation center Rc of the table 110 to be inspected. The imaging size is the size of the object P in the image, and may be output as the area or the number of pixels, for example. Moreover, when the shape of the object P is symmetrical such as a sphere, the size may be replaced by the length such as the diameter instead of the area.

Step of determining resolution (Step C)
Step C is a step of determining the resolution based on the detected position of the object P output in step B. FIG. In this embodiment, the pixel-by-pixel resolution _RI is determined for each pixel line in the circumferential direction. Specifically, in step C, as shown in FIG. 5, the _resolution determination unit 220 _determines the pixel-by-pixel resolution R _I to decide. The pixel-by-pixel resolution _RI may be determined by any method depending on the imaging means of the image acquisition unit 100 . For example, the pixel-by-pixel resolution _RI can be determined based on the following equation.

Step of correcting imaging size (step D)
In step D, the imaging size correction unit 230 corrects the variation in the imaging size caused by the rotation of the table 110 to be inspected based on the resolution determined in step C (resolution R _I per pixel), thereby correcting the authenticity of the object P. Size. In this embodiment, the number of pixels N _I (N ₁ to N ₆ ) for each pixel line (I ₁ to I ₆ ) is multiplied by the pixel resolution R _I determined in step C (N _I ×R _I ) , the imaging size is corrected for each pixel line. Here, a plurality of pixel lines are included in the picked-up image of the object P composed of a plurality of pixels, and the image pickup size varies at different rates for each pixel line. Therefore, in the present embodiment, based on the number of pixels _NI as the imaging size, the size variation is corrected for each pixel line.

After correcting the imaging size for each pixel line as described above, the sum of the corrected imaging sizes for all the pixel lines (I ₁ to I ₆ ) of the object P is taken to obtain the true size. The number of pixels _NI may be calculated by an appropriate method based on the imaging size detected in step B.

Process for judging the quality of inspection (process E)
In step E, the quality of the inspection is judged based on the true size obtained in step D. For example, if the genuine size is larger than a size predetermined as the allowable size of the object P, it may be determined that there is an abnormality, and if it is smaller, it may be determined that there is no abnormality.

(4) Effect According to the first embodiment, one or more of the following effects can be obtained.

(a) According to the inspection apparatus 10, even when the array of imaging elements extending in the radial direction of the table 110 to be inspected is used, variations in the imaging size from the actual size (genuine size) can be corrected. Therefore, it is possible to quickly determine the quality of the inspection based on the true size.

(b) In this embodiment, since the array of imaging elements extending in the radial direction of the table to be inspected 110 is provided, jigs and the like other than the camera 120 can be arbitrarily arranged on the table to be inspected. In the inspection apparatus 10, the entire inspection table 110 can be imaged without blind spots due to jigs or the like by taking an image while rotating the inspection table 110 once.

(c) In the present embodiment, the pixel-by-pixel resolution _RI is determined for each pixel line, and the imaging size is corrected for each pixel line. Thus, the true size can be obtained by repeating a relatively simple procedure.

(d) When a line camera is used as the camera 120 in the image acquisition unit 100, it is easy to keep the illumination amount of the imaging range uniform. Therefore, when the target object P is detected by the target object detection unit 210, it is easy to accurately detect the detection position and imaging size of the target object P by image processing.

<Second embodiment>
Next, the second embodiment will be described mainly about the differences from the first embodiment.

(1) Configuration of Inspection Apparatus 10 The configuration of the inspection apparatus 10 includes an image acquisition unit 100, an object detection unit 210, a resolution determination unit 220, an imaging size correction unit 230, and a quality determination unit 240, as in the first embodiment. It is configured to include Of these, the resolution determination unit 220 and the imaging size correction unit 230 may have the same configuration as in the first embodiment, while the specific procedures for determining the resolution and correcting the imaging size are performed as described below. .

(2) Procedure of inspection method In the second embodiment, as described below, in steps C and D, the representative resolution RG representing each object P based on the barycentric coordinates _Gc is used to inspect the object P. A procedure different from that of the first embodiment is adopted in terms of correcting the imaging size. Acquisition of an image on the table 110 to be inspected in process A and detection of the detection position and imaging size of the object P in process B may be performed in the same procedure as in the first embodiment.

Since the object P is imaged with a different resolution for each pixel line, correction for each pixel line is necessary to correct the imaging size. However, the method of correcting the imaging size for each pixel line tends to increase the processing load. For this reason, depending on the purpose of inspection, a method capable of processing in a shorter time may be required. Against this background, this embodiment employs a method of correcting the imaging size using the representative resolution _RG based on the barycentric coordinates Gc.

Here, representative resolution _RG based on the center-of-gravity coordinate Gc, which is different for each of a plurality of pixel lines, will be described. As described above, the resolution differs for each pixel line, and the resolution for each pixel line is in a linear relationship (proportional relationship) with the radius (center-to-center distance) based on the rotation center Rc. For this reason, when the resolutions of adjacent pixel lines are compared, the resolutions of the pixel lines on the inner peripheral side and the outer peripheral side monotonously increase or monotonically decrease, and inversely monotonically change. From this, when the imaging size (the number of pixels, the area) of the target object P located on the inner peripheral side and the outer peripheral side of the pixel line is the same with respect to the predetermined pixel line, the resolution of the pixel line is used. The imaging size of the entire object P can be corrected. In this case, it is possible to cancel out the difference in resolution between a plurality of pixel lines existing on the inner peripheral side and the outer peripheral side with respect to a predetermined pixel line. The predetermined pixel line is the pixel line on which the center of gravity of the object P is located.

As described above, the method of correcting the captured image size using the representative resolution _RG based on the barycentric coordinate Gc can reduce the processing load during correction while appropriately obtaining the true size. Processes C and D regarding the method of correcting the imaging size using the representative resolution _RG will be described in detail below.

Step of determining resolution (step C)
In the process C of the present embodiment, as shown in FIG. 6, the barycentric coordinate Gc of the object P with respect to the rotation center Rc of the inspection table 110 is obtained, and the representative resolution R G that is representative of each object P is calculated based on the barycentric coordinate _Gc. to decide. By using the representative resolution _RG , in the image size correction in step D, the image size can be collectively corrected based on the representative value. Here, the center-of-gravity coordinate Gc may be appropriately determined by a known method. For example, it can be determined using library data that is geometrically determined based on the contour shape of the object P on the image.

Step of correcting image size (step D)
In step D, the imaging size is corrected using the representative resolution _RG determined in step C. Specifically, a value obtained by multiplying the total number of pixels N _A of the object P by the representative resolution R _G (N _A ×R _G ) is set as the true size. In this embodiment, by using a representative value summarizing different resolutions for each pixel line, it is possible to correct the imaging size in step D at one time.

(3) Effects According to the second embodiment, in addition to the effects obtained in the first embodiment, one or more of the following effects can be obtained.

(a) By determining the representative resolution _RG for each object P based on the barycentric coordinates Gc, the imaging size can be corrected at once. In particular, when the barycentric coordinate Gc is obtained using library data as described above, the barycentric coordinate Gc can be efficiently determined for the object P, and the inspection can be performed in a short time. Become.

(b) Especially in an inspection in which many wide objects P are detected in the radial direction (XY direction) of the inspection table 110, the effect of shortening the inspection time in this embodiment is significant. In the method of determining the resolution _RI for _each pixel for each pixel line, the number of corrections of the imaging size increases as the width of the object P increases. This is because the imaging size can be corrected.

<Other embodiments>
The embodiments of the present disclosure have been specifically described above. However, the present disclosure is not limited to the above-described embodiments, and can be variously modified without departing from the scope of the present disclosure.

With respect to the object P to be inspected by the inspection apparatus 10, only objects P of a specific size or larger are subject to detection, and objects P of a specific size or smaller (for example, too fine) are not subject to inspection. good. Also, an example in which the object detection unit 210, the resolution determination unit 220, the imaging size correction unit 230, and the quality determination unit 240 are configured in the information processing apparatus 200 has been described. good.

In the above-described embodiment, the case of imaging the object P remaining on the inspection table after removing the inspection object on the inspection table 110 has been described, but the present invention is not limited to this. For example, when an image is acquired while an object to be inspected exists on the inspection table 110, it is possible to inspect whether or not foreign matter is mixed into the object to be inspected. In this case, the object to be inspected is of the same quality as the object P. However, the object to be inspected and the object P do not necessarily have to be of the same quality, and the material of the object to be inspected and the object P may be different. Also, the material of the object to be inspected and the object P may be the same, and only the size may be different.

REFERENCE SIGNS LIST 10 inspection device 100 image acquisition unit 110 inspection table 120 camera 200 information processing device 210 object detection unit 220 resolution determination unit 230 imaging size correction unit 240 pass/fail determination unit

Claims (5)

an image acquisition unit that acquires an image on a rotating inspection table using an imaging element array extending in a radial direction of the inspection table;
an object detection unit that detects a detection position and an imaging size of an object captured in the image;
a resolution determination unit that determines resolution based on the detected position of the object;
an imaging size correcting unit that corrects the variation of the imaging size caused by the rotation of the table to be inspected based on the resolution and sets the object to the true size;
An inspection apparatus comprising: a pass/fail determination unit that determines pass/fail in an inspection based on the true size. The resolution determination unit calculates a resolution for each pixel for each pixel line in the circumferential direction of the table to be inspected,
The inspection according to claim 1, wherein the imaging size correction unit corrects the imaging size by the pixel-by-pixel resolution, and sets the sum of the corrected imaging sizes for each pixel line as the true size of the object. Device. The resolution determination unit obtains coordinates of the center of gravity of the object with respect to the center of rotation of the table to be inspected, and determines a representative resolution representing each object based on the coordinates of the center of gravity,
The inspection apparatus according to claim 1, wherein the imaging size correcting unit corrects the imaging size of the object using the representative resolution. The resolution determination unit obtains the barycentric coordinates using library data for geometrically obtaining the barycentric coordinates of the object based on an outline shape of the object on the image including the variation of the imaging size. The inspection device according to claim 3. The inspection apparatus according to claim 1 or 3, wherein the image acquisition section acquires the image using a line camera.

Images