JP2018072252A - Device and method for inspecting surface of spherical object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device that can inspect the surface of a spherical object rapidly and accurately.SOLUTION: An inspection controller 10 includes: a rotational unit 11 for rotating a supplied spherical object B; an illumination unit 12 for emitting sheet-like white light on the surface of the spherical object B; an imaging unit 13 for imaging the white light emitted on the surface of the rotating spherical object; an adjusting unit 14 for changing the direction of the spherical object B; a supply unit 15 for supplying the spherical object B; and a control unit 16 for controlling the operations of the units and inspecting the surface of the spherical object B. The control unit 16 includes: an image processing unit 17 for processing a two-dimensional image obtained from the imaging unit 13; and a defect detecting unit 18 for detecting a defect in the surface of the spherical object B based on information obtained from the image processing unit 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inspection apparatus for inspecting the surface of a sphere and a method for inspecting the surface of a sphere.

A golf ball is composed of a core and a synthetic resin cover that covers the outer periphery of the core. A molding die that can be divided into two parts is used for molding the cover. For example, a compression molding method in which the core is wrapped with two preformed hemispherical shells and compression molded with a molding die, or the core is supported by a support pin or the like in the center of the cavity of the molding die, There is an injection molding method in which a molding material is injected into the gap between the core and the inner surface of the mold, and at the same time, a support pin is pulled out and cooled.
In these productions, defects such as scratches, pin burrs (bulges formed around the dimples), and welds (holes formed by gas generated from the filled resin) may occur on the surface of the golf ball. In addition, after molding, the burrs formed on the parting lines of the two molds are polished, but there are cases where swelling (scratch) due to sweet polishing or dents (too slipping) due to excessive polishing may occur. .

  Automation of detection and measurement of defects on the surface of such a golf ball has been attempted. For example, in Patent Document 1, a golf ball rotated at a constant speed is irradiated with light, photographed with a line camera along a line orthogonal to the rotation direction, and a two-dimensional image obtained from the image data of the line camera An inspection apparatus that recognizes a defective portion from a change in luminance of the two-dimensional image is disclosed. Patent Document 2 discloses a test for identifying a relative change in height of the surface of the golf ball by irradiating the surface of the golf ball with laser light and detecting the positional relationship between the laser light irradiation position and the light receiving portion. An apparatus is disclosed.

Japanese Patent Laid-Open No. 9-292349 Japanese Patent Laid-Open No. 11-30508

However, in Patent Document 1, since a defective portion is detected while comparing a change amount obtained by converting a luminance change in a rotation direction of a ball appearing on a two-dimensional image for each predetermined unit, defects such as scratches are the same as dimples. As described above, when the luminance change is caused, it is difficult to detect the defect. In addition, when irradiating light to the sphere, the light irradiation angle with respect to the surface of the sphere gradually increases toward both ends of the light, and the luminance changes. Further, when a printed matter such as a mark is provided, the luminance changes according to the printed matter. For this reason, it has been difficult to accurately grasp the dimple shape only by the luminance change. On the other hand, Patent Document 2 performs a three-dimensional inspection and has high measurement accuracy, but is spot measurement, so that it takes too much time to inspect the entire golf ball.
Further, although Patent Document 1 and Patent Document 2 detect dimple-shaped defects, they do not inspect the color of a mark or the like of a golf ball, and such inspection has to be performed in another process. In particular, the final inspection before boxing for dirt and the like is currently performed by visual inspection by an operator.
An object of the present invention is to provide an inspection apparatus and an inspection method that can accurately and accurately perform surface inspection of a spherical object.

  The apparatus for inspecting the surface of a sphere according to the present invention includes a rotating unit that rotates the sphere, an illumination unit that irradiates the surface of the sphere with sheet-like white light parallel to a rotation axis, and a surface of the sphere. An imaging unit that acquires a two-dimensional image obtained by imaging the irradiated white light, a first processing unit that acquires a surface height image of the sphere by processing a light cutting line of the two-dimensional image, and the two-dimensional An image processing unit having a second processing unit for processing a light cutting line of an image to obtain a surface color image of the sphere, and a first for detecting a defect on the surface of the sphere based on the surface height image And a defect detection unit having a second detection unit that detects a defect on the surface of the spherical object based on the surface color image.

  The inspection apparatus of the present invention can simultaneously detect a defect on the surface of the sphere by the first detector and detect a defect on the surface of the sphere by the second detector. The first detection unit can detect a defect such as a three-dimensional shape or a flaw on the surface of the sphere using the surface height image. The second detection unit can detect defects in the shape, pattern, color, etc. of the figure such as a mark on the surface of the sphere using the surface color image. In particular, since each defect is detected by acquiring inspection data (surface height image and surface color image) suitable for each inspection, it can be accurately and quickly performed. Furthermore, since two inspection data (surface height image and surface color image) used for different inspections are acquired from the same two-dimensional image, the illumination unit and the imaging unit can be shared, which is necessary for the inspection apparatus. Parts can be minimized. Thus, the inspection apparatus of the present invention is suitable as a final inspection apparatus in the manufacturing process of a sphere.

  The inspection apparatus according to the present invention preferably includes a pair of rotation support portions that sandwich the spherical object from both sides. In this case, since the sphere is firmly held, the sphere can be stably rotated at a constant speed.

  In the inspection apparatus of the present invention, it is preferable that the amount of light at both ends of the sheet-like white light is larger than the amount of light at the center of the sheet-like white light. When illuminating a sphere with sheet-like light, the reflected light intensity gradually decreases as it goes toward both ends of the sheet-like white light, but by increasing the light intensity at both ends of the sheet-like white light The change in luminance can be reduced, and a uniform level of reflected light can be obtained.

  The inspection apparatus of the present invention is preferable as an inspection apparatus for inspecting a sphere having a concave portion and / or a convex portion on the surface. In particular, the inspection apparatus of the present invention is preferable as an inspection apparatus for inspecting the surface of a golf ball having a large number of dimples on the surface.

The inspection apparatus according to the present invention, wherein the surface height image is an image showing the distance between the surface of the sphere and the reference surface in a direction perpendicular to the reference surface of the sphere in shades. preferable.
In the present invention, the “reference surface of a sphere” refers to the surface of a sphere assuming that there is no unevenness.
The image of the surface height image showing the distance between the surface of the sphere and the reference surface in a direction perpendicular to the reference surface of the sphere is shown by the brightness of the reflected light due to the curved shape of the sphere and the unevenness of the surface. Changes do not appear on the image. In addition, a change in the brightness of reflected light due to marks or the like provided on the surface of the sphere does not appear on the image. Therefore, the uneven shape (including scratches) on the surface of the sphere can be accurately recognized.

In the inspection apparatus of the present invention, it is preferable that the surface color image is an image obtained by developing the surface of the sphere in a plane, and is a plane correction image showing the color of the surface of the sphere.
By using the surface color image as a flat correction image, when the mark on the curved surface of the sphere is viewed from a predetermined position, distortion of the mark or the like that occurs as the distance from the center can be minimized. Therefore, it is possible to accurately recognize the shape, pattern, and color of the mark on the surface of the sphere.
In particular, the planar correction image is preferably an image viewed substantially perpendicular to the reference surface of the sphere. In this case, not only the curved shape of the sphere, but also distortion of marks and the like caused by surface irregularities can be minimized. For example, even if a printed matter such as a mark is provided in the recess, the shape of the printed matter such as the mark can be clearly displayed on the image while minimizing the influence of the recess, thereby further accurately detecting defects. be able to.

In the inspection apparatus of the present invention, it is preferable that the surface color image is an orthographic projection image of a spherical object centered on a portion to be inspected.
Here, the “orthographic projection image of a sphere” refers to an image obtained by projecting a sphere onto a plane with a light source at infinity.
By making the surface color image an orthographic projection image of a sphere centered on the portion to be inspected, the distortion of the mark or the like due to the curved shape of the sphere and the surface irregularities is small in the portion to be inspected. Therefore, the mark on the surface of the sphere can be accurately recognized.

The method for inspecting the surface of a sphere according to the present invention includes a step of rotating a sphere, a step of irradiating the surface of the sphere with sheet-shaped white light parallel to a rotation axis, and a surface of the sphere. Obtaining a two-dimensional image obtained by imaging the white light, processing a light cutting line of the two-dimensional image to obtain a surface height image of the sphere, and a light cutting line of the two-dimensional image Obtaining a surface color image of the sphere by processing the surface, detecting a defect on the surface of the sphere based on the surface height image, and a surface of the sphere based on the surface color image And a step of detecting the defect.
Since the inspection method of the present invention acquires two inspection data (surface height image and surface color image) used for different inspections by processing the same two-dimensional image, the number of steps can be reduced. In addition, it is possible to reduce the size and cost of the apparatus for this inspection.

In the inspection method of the present invention, it is preferable that the sphere is rotated by being supported by a pair of rotation support portions from both sides. In this case, the sphere can be rotated stably.
The inspection method according to the present invention is preferably supported by a rotation support portion of a sphere, and includes a step of changing the orientation of the sphere after the step of acquiring a two-dimensional image. When the sphere is supported by the rotation support portion and rotated, the area of the sphere supported cannot be inspected, but the entire surface of the sphere can be inspected smoothly by changing the direction.

In the inspection method according to the present invention, the step of processing the light cutting line of the two-dimensional image to obtain the surface height image of the sphere is corrected by bending the light cutting line of the two-dimensional image to perform the light cutting. A straight line is created, height information of the surface of the sphere is obtained from the light cutting straight line, and the surface of the sphere and the reference surface in a direction perpendicular to the reference surface of the sphere based on the height information It is preferable that it is a process of acquiring the surface height image which showed the distance with grey.
In the present invention, “curvature correction” refers to correction in which a curved light section line is made a straight line while maintaining its length. A straight line obtained by correcting the curved light cutting line is called a light cutting straight line. That is, the light cutting line before correction and the light cutting straight line after correction have the same length. As the curvature correction, a known image conversion method for correcting nonlinear distortion can be used in addition to polar coordinate conversion.
In the present invention, “height information” refers to information representing the position of the reference surface of a sphere and the difference in height between the reference surface and the surface of the sphere at that position (distance in the radial direction of the sphere).

  In the inspection method according to the present invention, the step of processing the light cutting line of the two-dimensional image to obtain the surface color image of the sphere is corrected to be curved to the light cutting line of the two-dimensional image and the light cutting straight line A surface corrected image showing the color of the surface of the sphere, which is obtained by obtaining the color information of the surface from the light cutting straight line and developing the surface of the sphere on a plane based on the color information. It is preferable that it is the process of acquiring.

  In the inspection method according to the present invention, the step of processing the light cutting line of the two-dimensional image to obtain a surface color image of the spherical object includes color information of the spherical object based on the light cutting line of the two-dimensional image. Preferably, this is a step of creating an attached three-dimensional model and acquiring an orthographic projection image centered on a portion to be inspected based on the three-dimensional model with color information.

It is a perspective view showing one embodiment of an inspection device of the present invention. It is a block diagram which shows the structure of the control part of the inspection apparatus of FIG. 3a and 3b are side views showing the standby state of the rotating unit and the sandwiching state of the sphere in the inspection apparatus of FIG. 1, respectively. 4A is a schematic diagram illustrating a relationship between the illumination unit and the imaging unit of the inspection apparatus illustrated in FIG. 1, and FIG. 4B is a schematic diagram illustrating an optical path difference between the reference surface and the concave portion of the spherical object. 5a and 5b are side views showing the standby state of the orientation adjustment unit and the holding state of the sphere in the inspection apparatus of FIG. 1, respectively. 6a, 6b, and 6c are perspective views showing a spherical object supply process, a spherical object inspection process, and a spherical object orientation adjustment process, respectively, of the inspection apparatus of FIG. 7a is a flowchart showing an operation procedure of the control unit of the inspection apparatus of FIG. 1, FIG. 7b is a flowchart showing an operation procedure of the first processing unit of the image processing unit, and FIG. 7c is a flowchart showing the operation procedure of the image processing unit. It is a flowchart which shows the operation | movement procedure of 2 process parts. FIG. 8a is a two-dimensional image of a golf ball, FIG. 8b is a schematic diagram of a light section line, and FIGS. 8c and 8d are schematic diagrams showing the concept of coordinate transformation. 9a is a two-dimensional image after polar coordinate transformation, FIG. 9b is a schematic diagram of a light cutting straight line after polar coordinate transformation, FIG. 9c is a schematic diagram showing the concept of the center of gravity point in the width direction of the light cutting straight line, FIG. 9d is a schematic diagram showing the concept of the center point in the width direction of the light-cutting straight line. Fig. 10a is an image showing a height-shade line (height information of the irradiated surface), and Fig. 10b is a surface height image. FIG. 11a is a schematic diagram showing how to obtain a color straight line from a light cutting straight line, and FIG. 11b is a surface color image. It is a flowchart which shows the operation | movement procedure of the 2nd process part of the test | inspection apparatus which is other embodiment of this invention.

  Next, an embodiment of an inspection apparatus for inspecting the surface of a sphere according to the present invention will be described with reference to the drawings. The inspection apparatus according to the present embodiment targets golf balls having dimples (hereinafter referred to as recesses) on the surface. However, the present invention is not limited to the following embodiments. Therefore, the spherical object to be inspected may be a bearing ball, an industrial plastic ball, a table tennis ball, or the like, or may have a convex or concave shape on the surface. In addition to the golf ball, for example, a soft baseball, a hard baseball, volleyball, basketball, and the like can be given.

  The inspection apparatus 10 of FIG. 1 irradiates the rotating unit 11 that rotates the distributed sphere B, the illumination unit 12 that irradiates the surface of the sphere B with sheet-like white light, and the surface of the rotating sphere B. An imaging unit 13 that captures the white light, a direction adjustment unit 14 that changes the orientation of the sphere B, a supply unit 15 that supplies the sphere B, and controls the operation of the sphere B. And a control unit 16 for inspecting the surface. As illustrated in FIG. 2, the control unit 16 processes the two-dimensional image obtained from the imaging unit 13 and the surface defect of the sphere B based on information obtained from the image processing unit 17. And a defect detection unit 18 for detection.

As shown in FIGS. 3a and 3b, the rotating unit 11 rotates (spins) the spherical object B at a constant speed so as to secure an imaging range A including the irradiation surface L irradiated with the sheet-like white light. .
The rotation unit 11 includes a pair of rotation support units 21a and 21b opposed to each other with a gap on the rotation axis Z1, a drive unit 22 that rotates one rotation support unit 21a, and the rotation support units 21a and 21b as rotation axes. Actuators 23a and 23b that move back and forth in the Z1 direction are provided.

  The rotation support portions 21a and 21b are supported so as to be rotatable around the rotation axis Z1 and to be movable back and forth in the direction of the rotation axis Z1 (left and right direction in FIGS. 3a and 3b). In this embodiment, the frame 25 is supported by a pair of support columns 25a and 25b. Then, when the support columns 25a and 25b are moved back and forth in the direction of the rotation axis Z1 by the actuators 23a and 23b, the rotation support portions 21a and 21b are moved back and forth in the direction of the rotation axis Z1. The rotation support portions 21a and 21b are cylindrical bodies having a rotation axis Z1 as a central axis, and shaft cores 21a1 and 21b1 are provided on the rear surface. Moreover, it is a spherical surface having substantially the same inner diameter as the outer diameter of the spherical object B held by the tip inner surfaces 21a2 and 21b2. A soft protective surface may be provided on the tip inner surfaces 21a2 and 21b2 so as not to damage the surface of the spherical object B.

The drive unit 22 is fixed in the support column 25a and is connected to the shaft core 21a1 of the one rotation support unit 21a. The rotational speed of the drive unit 22 is controlled by the control unit 16.
The rotation speed can be appropriately selected according to the shutter speed of the imaging unit 13.
The number of rotations in one inspection is preferably 1 rotation or more, more preferably 1.2 rotations or more, and particularly preferably 1.4 rotations or more. Since there are many overlapping portions, it is preferably 2 rotations or less, more preferably 1.8 rotations or less, and particularly preferably 1.6 rotations or less.
In addition, you may connect the drive part 22 to both the rotation support parts 21a and 21b, respectively. In this case, both drive units are synchronized by the control unit 16.

The actuators 23a and 23b are respectively fixed in the columns 25a and 25b, and move the columns 25a and 25b back and forth in the direction of the rotation axis Z1. The driving is synchronized by the control unit 16 and moves the support columns 25a and 25b in opposite directions. That is, when the actuators 23a and 23b are driven in one direction, the columns 25a and 25b move simultaneously so as to approach each other, and when driven in the other direction, the columns 25a and 25b move simultaneously so as to separate from each other.
The support columns 25a and 25b may be fixed, and the rotation support portions 21a and 21b may be directly moved back and forth by the actuators 23a and 23b. The shaft cores 21a1 and 21b1 of the rotation support portions 21a and 21b may be expanded and contracted. Also good. In either case, only one of them may be movable in the direction of the rotation axis Z1. Furthermore, you may provide an elastic body in both or one rotation support part 21a, 21b so that the spherical body B may be pressed mutually with both rotation support parts 21a, 21b.

The rotating part 11 configured as described above operates as follows.
As shown in FIG. 3 a, the sphere B is supplied to the center of the rotation unit 11 in a state where the rotation support units 21 a and 21 b of the rotation unit 11 are separated from each other.
3B, when the sphere B is supplied, the rotation support portions 21a and 21b move on the rotation axis Z1 so as to approach each other, and the tip inner surfaces 21a2 and 21b2 come into contact with the sphere B and the sphere B Hold it so that it is pressed. And in this clamping state, the drive part 22 drives and the rotation support parts 21a and 21b rotate around the rotating shaft Z1. That is, the sphere B rotates.
When the inspection of the spherical object B is completed and the rotation of the spherical object B is stopped, the spherical object B is supported by the orientation adjusting unit 14 or the supply unit 15 described later, and the rotation support units 21a and 21b are moved away from each other, and the state shown in FIG. Return to.

  Since the rotating part 11 rotates by holding the spherical object B between the rotation support parts 21a and 21b, it rotates the spherical object B around the rotation axis Z1 without sliding with the inner surfaces of the distal ends of the rotation support parts 21a and 21b. Can do. That is, the sphere B can be accurately rotated at an arbitrary speed. In addition, a portion other than the rotation support portion on the surface of the sphere B (except for the region Z in FIG. 5B) is always open, and the region on which the surface can be inspected is wide. Therefore, the freedom degree of arrangement | positioning of the illumination part 12 and the imaging part 13 is high. For example, in this embodiment, the illumination part 12 and the imaging part 13 are arrange | positioned diagonally upward of an apparatus, and the diagonally upper part of the spherical body B is made into the imaging range A (refer FIG. 3b and FIG. 6b). However, the illumination unit 12 and the imaging unit 13 may be arranged obliquely below the apparatus, and the diagonally lower portion of the sphere B may be set as the imaging range.

The illuminating unit 12 irradiates the sheet-shaped white light toward the rotation axis in parallel with the rotation axis Z1 of the sphere.
Then, the sheet-like white light is irradiated so that the width of the irradiation surface is preferably 750 μm or less, more preferably 600 μm or less, and particularly preferably 550 μm or less in view of inspection accuracy. On the other hand, when the imaging unit 13 captures an irradiation surface of white light at an angle θ (see FIG. 4A) and the surface of the sphere B is uneven, a portion where the irradiation surface cannot be seen from the imaging unit is formed. For this reason, if the width of the irradiated surface is too small, the light cutting line is partially cut. Therefore, the sheet-like white light is preferably irradiated so as to be 1 μm or more.
On the other hand, in order to perform inspection uniformly, the sheet-like white color is such that the length of the irradiation surface is preferably 60% or more, more preferably 70% or more, particularly preferably 75% or more of the diameter of the sphere B. Irradiate light. Note that if the width of the white light is too long, the area other than the inspection part is irradiated, which causes measurement errors (noise) due to stray light. Therefore, the length of the irradiated surface is preferably 99% of the diameter of the sphere B. In the following, sheet-like white light is irradiated so as to be more preferably 95% or less, and particularly preferably 90% or less.

  Further, it is preferable that the sheet-like white light has a light amount that is higher at both end portions than at the center portion. When irradiating the surface of the sphere B with white light, the irradiation angle of the light with the surface of the sphere B gradually increases toward both ends of the light, and the brightness of the reflected light received by the imaging unit 13 gradually decreases. Become. That is, the luminance at both ends of the white light entering the imaging unit 13 is smaller than the luminance at the center of the white light. Therefore, by increasing the amount of light at both ends of the sheet-like white light, it is possible to reduce the change in luminance due to the change in the light irradiation angle due to the curvature of the surface of the sphere B. Note that the amount of white light may be continuously increased toward both ends, or may be increased intermittently. As a means for adjusting the amount of such white light, for example, a method of providing the illumination unit 12 with a filter for reducing the amount of light at the center can be cited.

The imaging unit 13 is an area camera that images a partial region (imaging range A, see FIG. 3 b) of the surface of the spherical object B including the sheet-like white light irradiation surface L from an angle different from that of the illumination unit 12. It is.
The imaging unit 13 acquires a number of two-dimensional images that are continuously captured while the sphere B rotates once. As the number of two-dimensional images increases, a more accurate surface height image and surface color image can be obtained. Therefore, the number of two-dimensional images that are continuously captured while the sphere is rotated once is preferably 100 or more, more preferably 500 or more, and particularly preferably 750 or more. If the number of sheets is too large, the number of processed sheets will be too large and the inspection speed will be slowed down. Therefore, the number of two-dimensional images that are continuously captured during one rotation of the sphere is preferably 2000 or less, more preferably 1500 or less, particularly preferably 1250 or less.
The shutter speed of the imaging unit 13 can be appropriately selected according to the rotation speed and the number of two-dimensional images. For example, since a large amount of light is required for imaging, the shutter speed of the imaging unit 13 is preferably 100 μs or more, more preferably 500 μs or more, and particularly preferably 700 μs or more. On the other hand, since the blurring of the image increases, the shutter speed of the imaging unit 13 is preferably 1500 μs or less, more preferably 1000 μs or less, and particularly preferably 500 μs or less.

  The angle θ between the illumination direction of the white light of the illumination unit 12 and the imaging direction of the imaging unit 13 is preferably 30 degrees or more, with the surface (imaging range) of the sphere B as the center, as shown in FIG. More preferably, it is 35 degrees or more, and particularly preferably 40 degrees or more. When the angle θ is larger, the displacement Δ (see FIG. 4B) of the recess B2 on the two-dimensional image with respect to the depth of the recess B2 can be increased, and the accuracy of the height information can be increased. On the other hand, if the angle θ is too large, the white light reflected by the irregularities on the surface of the sphere B enters the blind spot, and the light cutting line is easily interrupted, and the reflected light intensity entering the imaging unit 13 decreases. The angle is preferably 85 degrees or less, more preferably 80 degrees or less, and particularly preferably 75 degrees or less.

Since the illumination unit 12 and the imaging unit 13 are configured in this way, as illustrated in FIG. 4B, the reference surface of the sphere B is irradiated with sheet-shaped white light from the illumination unit 12 at an irradiation angle of 90 degrees. When a two-dimensional image is imaged from the illumination unit 12 by the imaging unit 13 at an angle θ, the depth of the recess B2 appears as a displacement Δ on the optical cutting line of the two-dimensional image. The displacement Δ at this time and the depth H of the recess B2 (the depth of the recess B2 with respect to the reference surface B1 (the surface of the spherical object assuming no recess)) can be expressed by the following relational expression. .
Formula 1: Δ = H · sin θ
Therefore, as described above, the illuminating unit 12 is arranged so that the sheet-like white light passes through the rotation axis Z1 (the irradiation angle with respect to the surface of the sphere B is 90 degrees). Δ can be increased. Moreover, the reflection intensity of the white light on the surface of the sphere B can be increased, and the installation of the illumination unit 12 is easy.

The direction adjustment unit 14 is a part that changes the direction of the sphere B. The rotating part 11 of the inspection apparatus 10 holds the sphere B between the rotation support parts 21a and 21b and rotates it, so that the area abuts against the rotation support parts 21a and 21b (areas at both ends of the sphere B) Z. Surface inspection (see FIG. 5b) is not possible. Therefore, the orientation of the spherical object B can be inspected by changing the orientation of the spherical object B by the orientation adjusting unit 14 and performing a plurality of inspections.
As shown in FIG. 5, the orientation adjusting unit 14 includes a pair of support portions 31a and 31b that are opposed to each other with a gap on the Z2 line intersecting the rotation axis Z1, and a drive unit 32 that rotates the one support portion 31a. And actuators 33a and 33b for moving the respective support portions 31a and 31b in the Z2 line direction. That is, the support portions 31a and 31b are provided at the same height as the rotation support portions 21a and 21b (see FIG. 1). The Z2 line is preferably orthogonal to the rotation axis Z1.

  The support portions 31a and 31b are supported so as to be rotatable around the Z2 line and movable back and forth in the Z2 line direction. In this embodiment, the frame body 25 is supported by a pair of support columns 25c and 25d. The columns 25c and 25d are moved by the actuators 33a and 33b, and the support portions 31a and 31b are moved in the Z2 line direction. The support portions 31a and 31b are cylindrical bodies having the Z2 line as a central axis, and shaft cores 31a1 and 31b1 are provided on the rear surface. Moreover, it is a spherical surface having substantially the same inner diameter as the outer diameter of the spherical object B held by the tip inner surfaces 31a2 and 31b2. A soft protective surface may be provided on the inner surface of the tip so as not to damage the surface of the sphere B. Note that a soft protective surface may be provided on the inner surface of the tip so as not to damage the surface of the spherical object B.

The drive unit 32 is fixed in the support column 25c and is connected to the shaft core 31a1 of the one support unit 31a. The rotation angle of the drive unit 32 is selected according to a range that can be inspected by rotating the sphere B once. Since the number of orientation adjustments by the orientation adjustment unit 14 increases excessively, the rotation angle is preferably 20 degrees or more, more preferably 45 degrees or more. On the other hand, if it is too large, the overlapping range becomes large, so 90 degrees or less is preferable. In addition, when the rotation of 90 degree | times or more is desired, time can be shortened by carrying out reverse rotation.
In addition, you may connect the drive part 32 to both the support parts 31a and 31b, respectively. In this case, both drive units are synchronized by the control unit 16.

The actuators 33a and 33b are respectively fixed in the columns 25c and 25d, and move the columns 25c and 25d back and forth in the Z2 line direction. The drive is synchronized by the control unit 16 similarly to the actuators 23a and 23b, and moves the columns 25c and 25d in opposite directions.
The support columns 25c and 25d may be fixed, and the support portions 31a and 31b may be directly moved, or the shaft cores 31a1 and 31b1 of the support portions 31a and 31b may be expanded and contracted. Further, in either case, only one of them may be movable in the Z2 line direction. Furthermore, you may provide an elastic body in both or one support part 31a, 31b so that the spherical body B may be mutually pressed by both support parts 31a, 31b.

The orientation adjusting unit 14 configured in this way operates as follows.
As shown in FIG. 5a, the surface of the sphere B is inspected while the support B 31a and 31b of the orientation adjustment unit 14 are separated from each other.
As shown in FIG. 5B, when the inspection is completed and the sphere B is stationary, the support portions 31a and 31b move on the Z2 line axis so as to approach each other, and sandwich the sphere B. And after the rotation support parts 21a and 21b of the rotation part 11 leave | separated from the spherical body B, the drive part 32 drives and the support parts 31a and 31b rotate around a Z2 line. That is, the sphere B rotates around the Z2 line, and the direction of the sphere B changes.
After changing the orientation of the sphere object B, the sphere object B is held between the rotation support parts 21a and 21b of the rotating part 11, and at the same time, the support parts 31a and 31b are moved away from each other and separated from the sphere object B. Then, the sphere B is inspected again in this direction.
The direction of one sphere B is preferably changed 2 to 5 times, particularly preferably 2 to 3 times.

  Since the rotation axis (Z2 line) is orthogonal to the rotation axis Z1 of the rotation unit 11, the orientation adjustment unit 14 can transfer the spherical object B without interfering with each other. In addition, the rotation axis Z1 and the Z2 line may have an angle of less than 90 degrees within a range where the operations do not interfere with each other. Moreover, since the spherical object B is pinched by the support parts 31a and 31b similarly to the rotating part 11, the spherical object B can be accurately rotated.

The supply unit 15 carries the spherical object B from below the frame body 25 to the inspection position.
As shown in FIG. 6a, the supply unit 15 includes a hole 15a provided at the center of the frame body 25 and a support unit 15b that moves up and down in the hole 15a. The upper surface 15b1 of the support portion 15b is a spherical surface so as to support the sphere B (see FIG. 6b).

After receiving the sphere B below the frame 25, the support portion 15b ascends and carries the sphere B to the inspection position. At the same time as the spherical object B is sandwiched between the rotation support portions 21a and 21b, it moves to the standby position (see FIGS. 6b and 6c). When the inspection is completed, the sphere B is raised and received, and the sphere B is lowered and discharged out of the frame 25 to receive the next sphere B.
In addition, the columnar support part 15b that moves up and down may be rotated around the axis while the spherical body B is supported on the support part 15b of the supply part 15. In this case, the support part 15b of the supply part 15 acts as an orientation adjustment part. In this case, since the orientation adjustment unit 14 in FIG. 1 is not necessary, the side surface of the inspection apparatus 10 is opened, and the degree of freedom of other parts is increased.

  As shown in FIG. 2, the control unit 16 processes the light cutting line of the two-dimensional image to process the light cutting line of the two-dimensional image and the first processing unit 17a that acquires the surface height image of the sphere B. An image processing unit 17 having a second processing unit 17b for acquiring a color image of the surface of the sphere B, and a first detection unit 18a for detecting a three-dimensional defect on the surface of the sphere B based on the surface height image. And a defect detector 18 having a second detector 18b for detecting a color defect on the surface of the sphere B based on the surface color image. The control unit 16 controls operations of the rotation unit 11, the illumination unit 12, the imaging unit 13, the orientation adjustment unit 14, and the supply unit 15.

Next, an example of the operation of the control unit 16 is shown in FIG. 7A with reference to FIG.
After the start, the spherical body B is supplied to the inspection position by the supply unit 15 (S1, see FIG. 6a).
The spherical body B is sandwiched by the rotating unit 11, and the spherical body B is rotated at a constant speed (see S2, FIG. 6b).
The illumination unit 12 is irradiated with the sheet-like white light on the surface of the rotating sphere B (see S3, FIG. 6b).
The imaging unit 13 is caused to continuously acquire a number of two-dimensional images obtained by imaging the imaging range A of the surface of the spherical object B including the white light irradiation surface L (see S4, FIG. 6b). The imaging unit 13 acquires, for example, 1000 two-dimensional images while rotating the sphere.
Next, the image processing unit 17 captures the two-dimensional image, and processes the optical cutting line of the two-dimensional image to calculate the surface height image of the sphere B and the surface color image of the sphere B (see S5 and FIG. 6b). ). Here, it is preferable that the two-dimensional image is taken into the image processing unit 17 as needed every time it is acquired by the imaging unit 13. That is, it is preferable to simultaneously process the two-dimensional image previously captured while the imaging unit 13 is capturing an image. The operation of the image processing unit 17 (step S5A by the first processing unit 17a and step S5B by the second processing unit 17b) will be described later.
The defect detection unit 18 is caused to inspect the surface of the sphere B (detect a surface defect) based on the surface height image and the surface color image (S6, see FIG. 6b). That is, two operations of the first detection unit 18a and the second detection unit 18b of the defect detection unit 18 are performed. It is preferable to perform them simultaneously.
After confirming the end of the inspection, 1 is added to the counter number, and it is confirmed whether the counter value is N (S7). When the counter number is N, the supply unit 15 causes the spherical object B to be discharged from the inspection apparatus 10 and the process is terminated. When there is a next sphere B, the process returns to the start.
On the other hand, when the number of the counter is smaller than N, the direction adjusting unit 14 is caused to change the direction of the sphere B (see S8, FIG. 6c). Thereafter, the process returns to step S2.
The number N of the counter is selected according to the number of rotations of the rotating unit 11, the size (length) of the irradiation surface of white light, the angle of the orientation adjusting unit 14, and the like. Preferably 2 to 5 times, particularly preferably 2 to 3 times. Moreover, you may change the angle of the direction adjustment part 14 according to the number of a counter. For example, when the sphere B is rotated 1.5 times on the rotating unit 11 in one inspection, the counter number is set to rotate 60 degrees when the counter is 2 and reverse 60 degrees when the counter is 3. You may make it rotate to a different angle.

  Next, an operation (step S5) of the image processing unit 17 will be described. The image processing unit 17 has an operation (step S5A) by the first processing unit 17a that acquires the surface height image and an operation (step S5B) by the second processing unit 17b that acquires the surface color image.

First, step S5A will be described.
The first processing unit 17a of the image processing unit 17 obtains a surface height image of a sphere that indicates the distance between the surface of the sphere and the reference surface in a direction perpendicular to the reference surface of the sphere in shades. Specifically, the light cutting line of the two-dimensional image is curved to create a light cutting straight line, the height information of the sphere surface is obtained from the light cutting straight line, and the surface height image is created based on the height information. To do.

An example of the operation procedure of step S5A is shown in FIG. 7b.
The optical cutting line of the two-dimensional image is subjected to polar coordinate conversion (curvature correction), and converted from a substantially elliptical arc-shaped light cutting line to a substantially linear light cutting line (step S5A-1).
A barycentric point in the width direction of the light-cutting straight line subjected to polar coordinate conversion is obtained (step S5A-2).
A gray value (luminance value) is set according to the coordinates of the center of gravity, and the height of each X coordinate of the light-cutting line is expressed in gray values. Information) is obtained (step S5A-3). Steps S5A-1 to S5A-3 are performed at least by the number n (for example, 1000 times) of two-dimensional images when the sphere is rotated once. The sum of all the information is the height information of the surface of the sphere. It is preferable to perform process S5A-1 to process S5A-3 at any time in the order of the acquired two-dimensional image. That is, it is preferable to process the previous two-dimensional image simultaneously with the operation of the previous process. However, you may carry out collectively in each process.
The height density lines of each irradiation surface obtained from the light cutting line of each two-dimensional image are connected in the order of imaging to obtain a surface height image of the sphere (step S5A-4).

Next, details of each operation will be described.
First, the optical cutting line of the two-dimensional image is converted into a polar coordinate to convert the substantially elliptical arc-shaped light cutting line into a substantially linear light cutting line (step S5A-1).
The light cutting line L1 of the two-dimensional image representing the cross-sectional shape of the irradiation surface of the sphere B has an elliptical arc shape. For example, FIG. 8a is a two-dimensional image when a golf ball is imaged, and it can be seen that the light cutting line on the image is curved in an elliptical arc shape. More specifically, as shown in FIG. 8b, the light cutting line L1 has a shape in which a part of the circumference of the ellipse (elliptical arc) is wavy.
A two-dimensional image obtained by irradiating the surface of a spherical object (hereinafter referred to as a “reference surface”) assumed to have no irregularities with sheet-like white light and imaging the reflected light of the irradiated surface of the spherical object is An elliptical light cutting line (hereinafter referred to as “reference light cutting line”) having a diameter on the rotation axis Z1 as a major axis appears (see FIG. 8d). Then, the coordinates of the point P on the irradiated surface in FIG. 8d are the straight line connecting the distance R between the center of the sphere B and the point P (the vertical axis (Y axis) in FIG. 8c) and the center of the sphere B and the point P. And the angle α of the rotation axis Z1 (horizontal axis (X axis) in FIG. 8c) is converted to a point P ′ in FIG. 8c to be horizontal (parallel to the X axis) from the reference light cutting line of the elliptical arc. Is converted into a straight reference light cutting line.
The light cutting straight line cL1 is obtained by converting the light cutting line L1 into the same polar coordinate as the light cutting line L1. As shown in FIG. 9b, the light cutting straight line cL1 has a shape in which a horizontal (parallel to the X axis) waved. The image in FIG. 9a is a polar coordinate transform of the two-dimensional image in FIG. 8a.

Next, the barycentric point in the width direction of the light-cutting straight line cL1, that is, the vertical direction (Y-axis direction) is obtained (step S5A-2). Since the light cutting straight line is undulated in the Y-axis direction, it can be seen that there is a recess on the surface of the sphere. However, as shown in FIG. 9b, the height is unclear because it appears as a band having a certain width depending on the thickness of the sheet-like white light sheet. By calculating the center of gravity of the irradiated surface (the surface of the sphere), the height of the recess can be clarified.
When obtaining the barycentric point, as shown in FIG. 9c, the luminance value is plotted with respect to the Y coordinate (width direction of the light cutting straight line) at a point where the X coordinate is x, A connected curve S is created, and a Y coordinate y _g that halves the area between the curve S and the predetermined luminance value cd ₁ by a line segment orthogonal to the Y axis is obtained.
The center point may be obtained instead of the center of gravity point. When obtaining the center point, as shown in FIG. 9d, the luminance value is plotted with respect to the Y coordinate (width direction of the light cutting line) at the point where the X coordinate is x, and the light cutting of the luminance value equal to or higher than a predetermined value The average Y coordinate y _m of the Y coordinates (maximum value y _H and minimum value y _L ) at both ends of the straight line is obtained. By taking the center point of the light section line in this way, it is possible to suppress the influence of the luminance change due to the printed mark or the like. Moreover, you may obtain | require the peak of a luminance value simply.
Line cL _g that connects the center of gravity of the light section line is as indicated by the imaginary lines in FIG. 9b, it is wavy. And the line cL _g and the reference light cut linear, except the portion which undulates the light cut linear are overlapping. That is, the displacement (Δ in FIG. 4 b) between the wavy portion line cL _g (the height of the surface of the sphere) and the reference light cutting straight line (reference surface) becomes the height of the concave portion of the sphere B. . By obtaining the center of gravity or the center point in this way, the height of each X coordinate becomes clear, and the calculation of the next process can be simplified.

Next, a gray value (luminance value) is set according to the coordinates of the barycentric point, and the height of each X coordinate is expressed as a gray value. Information) is obtained (step S5A-3).
The X coordinate indicating the horizontal position of the light cutting straight line corresponds to the X coordinate of the reference light cutting straight line, and corresponds to the position of the reference surface. In other words, as shown in FIG. 10a, the height gradation line of the irradiated surface is the position of the reference surface of the sphere on the irradiated surface and the difference in height between the reference surface and the surface of the sphere at that position (the radial direction of the sphere). Information).
The gray value g _x of the center of gravity when the X coordinate is x can be expressed as follows by the Y coordinate (y _m ) of the center of gravity.
Formula 2: g _x = k ₁ · y _m + k ₂
Here, k _1, k _2, the maximum value of the gray value when the Y coordinate of y _m as shown in Figure 10a is the maximum value (white), and the gray value when the Y coordinate of y _m is the minimum value It is preferable to set so as to be the minimum value (black). However, k ₁ and k ₂ may be set arbitrarily.
As described above, in steps S5A-1 to S5A-3, a height shading line (height information of the irradiation surface of the sphere B) is obtained from the light cutting line of one two-dimensional image. This height-shade line is a straight line image in which the irradiated surface is viewed substantially perpendicular to the reference surface, and is a straight line image showing the distance between the surface of the irradiated surface and the reference surface in light and shade.

Next, the height-shade lines obtained from the light cutting lines of the respective two-dimensional images are connected in the order in which they are picked up to obtain a surface height image of the sphere (step S5A-4).
At this time, the height shading line is used as the luminance value of the arrangement of the pixels in the X-axis direction at a predetermined Y coordinate, and the height shading lines acquired continuously are slightly shifted in the Y-axis direction and synthesized. The amount not in the Y-axis direction is preferably equal to the distance that the surface of the sphere moves in the rotational direction between successive imaging. Then, it is preferable to adjust the rotation amount and the imaging interval so that the shift amount is one pixel in the Y-axis direction.
A surface height image of the synthesized sphere B can be obtained by connecting all of the many shade lines of height. That is, an image in which the surface of the sphere is viewed substantially perpendicular to the reference surface and the distance between the surface of the sphere and the reference surface is shown in shades. FIG. 10b is a golf ball surface height image. The X axis of the surface height image is a latitude line of a sphere with the rotation axis as the ground axis, and is an irradiation surface of each light cutting line. It is preferable that the surface height image can be calculated quickly by creating the images by connecting them in the order of the required height gray lines. However, it may be created after collecting all the height shading lines.

  The surface height image of the sphere B obtained in the first processing unit 17a (step S5A) is the surface without the concave portion of the sphere B when the Y coordinate is white and the Y coordinate is black. The portion corresponding to (place) is brightest, and the concave portion (dimple of the golf ball in FIG. 10b) is dark in proportion to the depth. That is, the surface height image does not show a change in the brightness of reflected light due to the printed shape such as the curved shape of the sphere, the shape of the concave portion on the surface, and the mark provided on the surface. Therefore, the uneven shape (including scratches) on the surface of the sphere can be accurately recognized. Thus, the surface height image is suitable for detecting a three-dimensional shape defect on the surface of the sphere B.

In this embodiment, the surface height image is obtained after creating a light-cutting straight line that has undergone curvature correction (polar coordinate conversion). However, the center of gravity (or center point) is obtained in the form of an elliptical arc without performing coordinate conversion. May be. However, in this case, the calculation becomes complicated.
In this embodiment, as the height information of the irradiated surface, the height-shade line of the irradiated surface is given, but for example, as shown in the table in which the position and height of the reference surface correspond to each other, the position and height of the reference surface There is no particular limitation as long as it shows a correspondence relationship.
In this embodiment, as the surface height image of the sphere object B, a 3D distance image in which the height is expressed by shading is exemplified. However, for example, an image obtained by capturing a 3D three-dimensional structure from a specific angle may be used. The image is not particularly limited as long as the position and height of the surface can be confirmed.

  The second processing unit 17b of the image processing unit 17 obtains a plane correction image that is an image in which the surface of the sphere is developed in a plane and shows the color of the surface of the sphere. Specifically, the light cutting line of the two-dimensional image is corrected to bend to create a light cutting straight line, color information on the surface of the sphere is obtained from the light cutting straight line, and a plane correction image is acquired based on the color information. In this embodiment, this plane correction image is a “surface color image”.

An example of the operation procedure of step S5B is shown in FIG. 7c.
The optical cutting line of the two-dimensional image is converted into a polar coordinate (curvature correction) to convert the elliptical arc-shaped optical cutting line into a substantially linear optical cutting line (step S5B-1).
A color straight line (color of the irradiated surface of the sphere) that represents the color of the surface of the sphere on the line (radial line) connecting the position of the reference surface of the sphere and the center of the sphere from the light cutting straight line Information) is acquired (step S5B-2). Steps S5B-1 to S5B-2 are performed at least for the number n (for example, 1000 times) of two-dimensional images when the sphere is rotated once. And it is preferable to perform process S5B-1 to process S5B-2 at any time in the order of the acquired two-dimensional image. That is, it is preferable that the previous two-dimensional image be processed simultaneously with the operation of the previous process. However, it may be performed collectively in each step.
A color correction image representing the surface of the sphere is obtained by connecting the color straight lines of the respective irradiation surfaces obtained from the light cutting lines of the two-dimensional images in the order of image pickup (step S5B-3).

Next, details of each operation will be described.
First, the optical cutting line of the two-dimensional image is subjected to polar coordinate conversion to convert from an elliptical arc shape to a substantially linear shape (step S5B-1). Polar coordinate conversion of the light section line is the same as in step S5A-1.

Next, a color straight line (color information of the irradiation surface of the sphere) is acquired from the light cutting straight line that has undergone polar coordinate conversion (step S5B-2).
As described above, the X coordinate indicating the horizontal position of the light cutting straight line is the same as the X coordinate of the reference light cutting straight line, and corresponds to the position of the reference surface.
On the other hand, with respect to the points where the X coordinate of the light-cutting line is x, points having luminance values equal to or higher than a predetermined value are given, and the average of the luminance values at those points is obtained. Note that the average of the luminance values is obtained for each of a plurality of single color images constituting the two-dimensional image. As a combination of single colors, a combination of colors that are white when combined is preferable. In particular, a combination of red, blue, and green is preferable because it is easily available. By obtaining the average value of the luminance of the color, it is possible to clear the plane correction image acquired in the next step.
A color straight line CL (color information of the irradiation surface of the sphere) is obtained by plotting the averaged luminance value on the reference light cutting straight line. As shown in FIG. 11, the color straight line CL can be considered as a straight line obtained by projecting the color information of the light cutting straight line cL1 onto a straight line having the same length. That is, the color straight line is an image obtained by viewing the irradiation surface substantially perpendicular to the reference surface.
As described above, one color line is obtained from the light section line of one two-dimensional image by the steps S5B-1 and S5B-2.

Next, the color straight lines are connected in the order of imaging to obtain a plane correction image (step S5B-3).
The color straight lines that are continuously acquired are combined while being shifted little by little in the Y-axis direction. The amount not in the Y-axis direction is preferably equal to the distance that the surface of the sphere moves in the rotational direction between successive imaging. Then, it is preferable to adjust the rotation amount and the imaging interval so that the shift amount is one pixel in the Y-axis direction.
By connecting all the many color straight lines, a plane correction image representing the surface of the sphere B can be synthesized. FIG. 11b is a plane correction image of the golf ball. It is preferable that the plane correction image can be calculated quickly by creating it by sequentially connecting it in the order of the required color straight lines. However, it may be created after collecting all the color straight lines.

  As described above, the plane corrected image of the sphere B obtained by the second processing unit has a curved surface of the sphere B developed in a plane, and thus there is no distortion of the mark or the like due to the curvature of the sphere B. Further, since the image is viewed from a direction substantially perpendicular to the surface of the sphere, there is no distortion of the mark or the like due to the concave portion on the surface of the golf ball. Therefore, it is suitable for inspection of dirt on the surface of the sphere B and inspection of marks on the surface of the sphere B.

In this embodiment, the averaging of the color in the width direction of the light section line is performed. For the point where the X coordinate is x, the barycentric point of the luminance value is calculated in the same manner as in step S5A-2 (see FIG. 9c). Then, the average luminance may be obtained by adding luminance values of a predetermined width up and down from the center of gravity. Thus, by obtaining the average luminance centered on the barycentric point, it is possible to more accurately remove the distortion of the mark or the like due to the unevenness of the golf ball surface. This is because, by using only the color information in the vicinity of the light section line, color information accurately corresponding to the height position of the irradiated surface can be acquired, and unevenness correction without noise can be performed.
Further, the plane correction image may be obtained by connecting the light-cutting straight lines in the order in which they are imaged without averaging the colors. In this case, the distortion caused by the irregularities on the surface of the spherical object cannot be suppressed as compared with the flat correction image in which the color straight lines are connected, but the calculation can be simplified. In this case, the light cutting straight line itself is the color information of the surface of the sphere.

  In the plane correction image obtained in this way, the curved surface of the spherical object and the distortion of the mark or the like corresponding to the surface irregularities do not appear. Therefore, the surface pattern can be recognized more accurately, which is more suitable for detecting a color defect on the surface of the sphere B. In particular, it is possible to accurately inspect printed marks and patterns. For example, when inspecting a mark or logo printed on a pad on a golf ball having a concave portion on the surface, distortion due to the concave portion is removed and accurate pattern matching is possible.

  Next, the operation (step S6) of the defect detection unit 18 will be described. The operation of the defect detection unit 18 includes an operation by the first detection unit 18a and an operation by the second detection unit 18b.

  The first detector 18a detects a three-dimensional shape defect on the surface of the sphere B based on the surface height image.

Next, an example of the detection method of the 1st detection part 18a is given.
The first detector 18a inspects the concave (or convex) shape, concave (or convex) size, and concave (or convex) interval on the surface of the sphere B based on the surface height image. Their size, shape, etc. may be inspected by comparison with a preset inspection threshold, or by comparison with a reference sample surface height image acquired in advance.
For example, when the inspection object is a golf ball and the surface height image is a gray-valued 3D distance image, the concave portion (dimple) is detected black, and the others are detected white. The surface inspection based on the 3D distance image is preferably performed as in the following (1) to (6).
(1) Overall inspection Inspect the entire area for extremely black or white areas. In the 3D distance image (surface height image), large burrs and scratches are detected as extremely black portions or white portions. In the case of a conventional 2D image, the light is hidden by large burrs or scratches, or is irregularly reflected and cannot be accurately detected.
(2) Inspection of recess interval Inspect whether there is an abnormality in the shape or area of the recess interval. By inspecting the interval between the recesses, it is possible to detect a portion where the recess is shallow (for example, a thread) or a portion where the recess is completely filled.
(3) Inspection of concave shape Inspect whether the concave shape is deformed. A distorted recess can be detected.
(4) Inspection in the recessed portion The recessed portion that was not caught by the inspection of the recessed portion shape is inspected for the presence or absence of a white portion or an extremely black portion in the recessed portion. In the 3D distance image, a bulge in the recess is detected as a white portion in the recess, and a hole (for example, a weld) in the recess is detected as an extremely black portion in the recess.
(5) Inspection outside the concave portion Examine the presence or absence of an extremely black or white portion other than the concave portion. In the 3D distance image, the bulge outside the recess is detected as an extreme white portion, and the dent outside the recess is detected as a black portion.
(6) Inspection around the recess The periphery of the recess refers to a boundary region between the inside of the recess and the outside of the recess. Inspect for extreme white areas in this area. In the 3D distance image, a bulge (for example, burr) around the concave portion is detected as an extreme white portion in this region.
In order to supplement the unevenness inspection of the 3D distance image, the unevenness inspection (particularly, the entire inspection) may be performed with the 2D color image simultaneously with the inspection of the 3D distance image as described above.

  Based on the surface color image, the second detection unit 18b detects defects such as the shape and color of printed matter and marks provided on the surface of the sphere B, and further inspects the surface of the sphere B, etc. . Specifically, the inspection is performed in comparison with a preset inspection threshold value or a reference sample image acquired in advance.

  The inspection apparatus 10 can substantially simultaneously detect a defect in the shape of the surface of the sphere object B and detect a defect in the color of the surface of the sphere object. In addition, surface height images are used for detecting defects in the shape of the surface of the sphere B, and surface color images are used for detecting defects in the color of the surface of the sphere B, and inspection data suitable for each defect detection is acquired. Therefore, it can be performed accurately and quickly. Furthermore, since the surface height image and the surface color image used for different inspections are acquired from the same two-dimensional image, the illumination unit and the imaging unit can be shared, and the inspection apparatus can be miniaturized. Thus, the inspection device 10 is optimal as a final inspection device for the sphere (golf ball) B.

  Next, a second embodiment (second processing unit 17b1) of the second processing unit of the inspection apparatus 10 will be described.

  The second processing unit 17b1 of the image processing unit 17 obtains an orthographic projection image of a spherical object centered on a portion to be inspected. Specifically, a 3D model with color information of a sphere is created based on the light section line of the 2D image, and an orthographic projection image centered on the portion to be inspected is acquired based on the 3D model with color information. . In this embodiment, the orthographic projection image is a “surface color image”.

An example of the operation procedure of step S5B1 is shown in FIG.
The coordinates (x, y, z) and color information at each point are acquired from the light section line of the two-dimensional image, and a three-dimensional model with color information is obtained based on them (step S5B1-1).
An orthographic projection image is acquired from the three-dimensional model with color information so that the portion to be inspected is centered (step S5B1-2).

Next, details of each operation will be described.
Three-dimensional coordinates and color information at each point are acquired from the optical cutting line of the two-dimensional image (step S5B1-1).
Two-dimensional coordinates (x, y) and color information on the two-dimensional image are directly obtained from the light section line of the two-dimensional image. On the other hand, each two-dimensional image is obtained by rotating a sphere at a constant speed and taking an image at a constant shutter speed. Therefore, from the information directly obtained from the light cutting line of the two-dimensional image and the acquisition time of the two-dimensional image in which the light cutting line is reflected, the two-dimensional coordinates on each two-dimensional image are converted to obtain the cubic of the sphere. The original coordinates can be obtained.
Then, a three-dimensional model with color information is obtained based on the obtained three-dimensional coordinates and color information.

An orthographic projection image is acquired from the three-dimensional model with color information so that the portion to be inspected is centered (step S5B1-2).
The orthographic projection image of the three-dimensional model is obtained by projecting the three-dimensional model onto a plane with a light source at infinity. The orthographic projection image of the three-dimensional model is distorted according to the curvature of the sphere as it moves away from the center. Therefore, the orthographic projection image is acquired so that the portion to be inspected is centered.

  In this way, since the orthographic projection image of the sphere B obtained by the second processing unit 17b1 is centered on the portion to be inspected, the distortion according to the curved surface of the sphere and the unevenness of the surface can be minimized. it can.

There is a sphere having a transparent layer containing a pigment, such as a colored golf ball such as yellow.
The sheet-like white light irradiated on the surface of such a spherical object enters the transparent layer as well as the surface, diffuses and reflects, and is received by the imaging unit 13.
In this case, since the light cutting line of the two-dimensional image has an enlarged width and the edge looks blurred, it is possible to accurately obtain an average value of the barycentric point (or center point) of the light cutting line and the luminance of the light cutting line. difficult.
When such a spherical object is to be inspected, a predetermined width is selectively cut out from a bright part (high brightness part) in the width direction of the light cutting line of the two-dimensional image, and the brightness of other parts is calculated as 0. By processing, the barycentric point (or center point) of the light cutting line and the average value of the luminance of the light cutting line can be obtained.
This method can be employed in any of the inspection apparatuses described above. Moreover, it can be used also for the test | inspection of the spherical object B from which white light reflects on the surface, and it is preferable.

A Imaging range B Sphere B1 Reference surface B2 Concave L Irradiation surface L1 Optical cutting line cL1 Optical cutting line Z Grasping area Z1, Z2 Rotating shaft 10 Inspection device 11 Rotating unit 12 Illuminating unit 13 Imaging unit 14 Orientation adjusting unit 15 Supply unit 15a Hole 15b Support section 15b1 Upper surface 16 Control section 17 Image processing section 17a First processing section 17b, 17b1 Second processing section 18 Defect detection section 18a First detection section 18b Second detection section 21a Rotation support section 21a1 Axis core 21a2 Tip inner surface 21b Rotation support portion 21b1 Axis core 21b2 Front end inner surface 22 Drive portions 23a, 23b Actuator 25 Frame bodies 25a, 25b, 25c, 25d Post 31a Support portion 31a1 Axis core 31a2 End end inner surface 31b Support portion 31b1 Axis core 31b2 End surface 32 Drive portion 33a 33b Actuator

Claims (14)

A rotating part for rotating the sphere,
An illumination unit that irradiates the surface of the spherical object with sheet-like white light parallel to the rotation axis;
An imaging unit that acquires a two-dimensional image obtained by imaging the white light irradiated on the surface of the spherical object;
A first processing unit that processes a light cutting line of the two-dimensional image to obtain a surface height image of the sphere, and a light color of the two-dimensional image to process a surface color image of the sphere. An image processing unit having a second processing unit;
A defect detection unit having a first detection unit that detects a defect on the surface of the sphere based on the surface height image and a second detection unit that detects a defect on the surface of the sphere based on the surface color image; With
Inspection device for the surface of a sphere. The rotating portion has a pair of rotation support portions that sandwich the spherical object from both sides.
The inspection apparatus according to claim 1. The amount of light at both ends of the sheet-like white light is greater than the amount of light at the center of the sheet-like white light,
The inspection apparatus according to claim 1 or 2. The sphere has a concave portion and / or a convex portion on the surface,
The inspection device according to claim 1. The sphere is a golf ball having a large number of dimples on the surface.
The inspection apparatus according to claim 4. The surface height image is an image showing the distance between the surface of the sphere and the reference surface in a direction perpendicular to the reference surface of the sphere in shades.
The inspection apparatus according to claim 1. The surface color image is an image obtained by developing the surface of the sphere in a plane, and is a plane correction image showing the color of the surface of the sphere.
The inspection apparatus according to claim 1. The surface color image is an orthographic projection image of the sphere around a portion to be inspected.
The inspection apparatus according to claim 1. Rotating the sphere,
Irradiating the surface of the spherical object with sheet-like white light parallel to the rotation axis;
Obtaining a two-dimensional image obtained by imaging the white light irradiated on the surface of the sphere,
Processing a light cutting line of the two-dimensional image to obtain a surface height image of the sphere;
Processing a light cutting line of the two-dimensional image to obtain a surface color image of the sphere;
Detecting defects on the surface of the sphere based on the surface height image;
Detecting defects on the surface of the sphere based on the surface color image,
Inspection method of the surface of a sphere. The step of rotating the sphere is a step of rotating the sphere at a constant speed by supporting the sphere with a pair of rotation support portions from both sides.
The inspection method according to claim 9. Comprising the step of changing the orientation of the sphere.
The inspection method according to claim 10. The step of processing the light cutting line of the two-dimensional image to obtain the surface height image of the sphere object corrects the curvature to the light cutting line of the two-dimensional image to create a light cutting straight line, and the light cutting straight line Surface height information of the sphere object is obtained from the surface, and based on the height information, the distance between the surface of the sphere object and the reference surface in a direction perpendicular to the reference surface of the sphere object is indicated by shading A step of acquiring a height image;
The inspection method according to claim 9. The step of processing the light cutting line of the two-dimensional image to obtain the surface color image of the sphere object creates a light cutting straight line by correcting the curvature of the light cutting line of the two-dimensional image, and from the light cutting straight line Obtaining color information of the surface of the sphere, and based on the color information, obtaining the plane correction image showing the surface color of the sphere, wherein the surface of the sphere is developed on a plane.
The inspection method according to claim 9. The step of processing the light cutting line of the two-dimensional image to obtain the surface color image of the spherical object creates a three-dimensional model with color information of the spherical object based on the light cutting line of the two-dimensional image, Based on a three-dimensional model with color information, it is a step of obtaining an orthographic projection image centered on a portion to be inspected,
The inspection method according to claim 9.

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