TW202113304A - Imaging apparatus, imaging method and inspection apparatus - Google Patents

Abstract

The present invention is provided with: a rotation driving unit for rotating a workpiece about a rotary axis; a first illumination unit for illuminating a cylindrical inner circumferential surface rotated by the rotation driving unit; and a first imaging unit for, with respect to the workpiece rotated by the rotation driving unit, locally capturing images of the cylindrical inner circumferential surface at an obliquely distanced position on one side of the workpiece in a horizontal direction so as to obtain first partial images of the cylindrical inner circumferential surface, wherein an entire circumferential image of the cylindrical inner circumferential surface is obtained by the first imaging unit obtaining the plurality of first partial images during at least one rotation of the workpiece about the rotary axis.

Description

Camera device, camera method and inspection device

The present invention relates to an imaging technique for photographing a workpiece having a cylindrical part such as a gear or a bushing, and an inspection technique for inspecting the workpiece.

The following descriptions of the Japanese application, drawings, and disclosure of the scope of the patent application, all of which are incorporated into this specification by reference: Japanese Patent Application 2019-171152 (filed on September 20, 2019).

In various devices such as machine tools and automobiles, many cylindrical parts are used to penetrate and install parts. Among these parts, other parts such as shafts or tubes are fitted into the cylindrical part. Therefore, it is necessary to check whether there are defects such as cracks or bubbles on the inner circumferential surface of the cylindrical part, that is, the cylindrical inner circumferential surface. Therefore, in the past, a device for photographing and inspecting parts with a cylindrical inner peripheral surface has been proposed. For example, in Japanese Patent Laid-Open No. 10-47929, a workpiece with a cylindrical part penetrating through the center is placed on the inspection table in a longitudinal posture in which the axis of the cylindrical part is parallel to the vertical direction. On the one hand, one of the openings (lower side opening) of the cylindrical part is blocked by the inspection table, and on the other hand, the other opening (upper side opening) is opened upward. In addition, the conical mirror is inserted into the cylindrical part through another opening, and is placed on the inspection table. Above the reflecting mirror, a camera is arranged to photograph the cylindrical inner peripheral surface of the workpiece. In this way, in the past, an imaging device formed by a combination of a mirror and a camera was used to take a full-periphery image of the cylindrical inner peripheral surface, and the judging means inspected the cylindrical inner peripheral surface of the workpiece based on the full-peripheral image.

The imaging device described in Japanese Patent Laid-Open No. 10-47929 uses a mirror corresponding to the shape and size of the cylindrical part of the workpiece. Therefore, the mirror must be remade according to the type of workpiece, which is poor in versatility.

The present invention was completed in view of the above-mentioned problems, and its purpose is to provide an imaging technique that can take images of a wide variety of workpieces with high versatility and is set on the cylindrical inner surface of each workpiece, and can inspect the cylindrical inner surface of each workpiece. Perimeter inspection technology.

The first aspect of the present invention is an imaging device for photographing a cylindrical inner peripheral surface of a cylindrical part that is penetrated with respect to a workpiece; The axis is aligned with the rotating shaft extending in the horizontal direction, and the workpiece is rotatably held around the rotating shaft; the rotating drive part rotates the workpiece held in the holding part around the rotating shaft; the first lighting part is opposite Illuminate the cylindrical inner peripheral surface rotated by the rotary drive unit; and the first imaging unit for the workpiece rotated by the rotary drive unit from a position on the side away from the workpiece in the horizontal direction from the oblique direction Partially capture the cylindrical inner circumferential surface to obtain the first partial image of the cylindrical inner circumferential surface; the entire circumferential image of the cylindrical inner circumferential surface is during the period when the workpiece rotates at least one revolution around the axis of rotation. The imaging unit acquires a plurality of first partial images.

In addition, the second aspect of the present invention is an imaging method for photographing a cylindrical inner peripheral surface of a cylindrical part penetrating through a workpiece; The step of rotating the workpiece around the axis of rotation while the axis of rotation extending in the horizontal direction is consistent; while the workpiece is rotating at least one revolution around the axis of rotation, the cylindrical inner peripheral surface of the workpiece that is rotating around the axis of rotation is illuminated The step of capturing the cylindrical inner peripheral surface from the oblique direction while being away from the position on one side of the workpiece in the horizontal direction to obtain plural first part images of the cylindrical inner peripheral surface; and according to the plural first part images To obtain the entire circumference image of the cylindrical inner peripheral surface.

In addition, a third aspect of the present invention is characterized in that it includes the above-mentioned imaging device; and an inspection unit that inspects the cylindrical inner peripheral surface based on a plurality of first partial images acquired by the imaging device.

In the invention thus constituted, the first imaging unit is separated from the workpiece in the horizontal direction while rotating the workpiece about the axis of rotation in the horizontal posture in which the axis of the cylindrical part coincides with the axis of rotation extending in the horizontal direction. Partially photograph the cylindrical inner peripheral surface from the oblique direction at one side position to obtain a first partial image of the cylindrical inner peripheral surface. The acquisition of the first partial image is performed while the workpiece rotates at least one revolution, and the entire circumference image of the cylindrical inner peripheral surface is acquired.

As described above, according to the present invention, the cylindrical inner peripheral surface is partially captured from the oblique direction while the workpiece is rotated at least one turn in the above-mentioned lateral posture to obtain a plurality of first partial images of the cylindrical inner peripheral surface. Obtain a full-circle image of the cylindrical inner peripheral surface. Therefore, regardless of the type of the workpiece, the cylindrical inner peripheral surface of the workpiece can be photographed, and higher versatility can be obtained.

The above-mentioned plural constituent elements of the various aspects of the present invention are not all necessary. In order to solve part or all of the above-mentioned problems, or to achieve part or all of the effects described in the specification of the case, the above-mentioned plural elements may be used. The constituent elements of a part of the constituent elements may be appropriately changed, deleted, replaced with new other constituent elements, or partially deleted with limited content. In addition, in order to solve part or all of the above-mentioned problems, or to achieve part or all of the effects described in the specification of the case, it is also possible to combine part or all of the technical features included in the above-mentioned aspect of the present invention with the above-mentioned present invention. Part or all of the technical features included in the other aspect are combined to form an independent aspect of the present invention.

Fig. 1 is a diagram showing the overall configuration of an inspection device equipped with a first embodiment of the imaging device of the present invention. The inspection device 1 is provided with: an imaging device 2 that photographs the inner peripheral surface Wb of the shaft hole Wa provided in the central portion of the spur gear W as an example of the "workpiece" of the present invention; and a control device 3 that controls the imaging device 2 and inspect the inner peripheral surface Wb based on a plurality of partial images captured by the imaging device 2. Furthermore, in the spur gear W, the shaft hole Wa corresponds to an example of the "cylindrical portion" of the present invention, and the inner peripheral surface Wb corresponds to an example of the "cylindrical inner peripheral surface" of the present invention. In addition, in order to clarify the positional relationship of the various parts of the device, the XYZ rectangular coordinate axis is shown in FIG. 1. That is, as described below, the X direction parallel to the horizontal direction in which the rotation axis AX1 of the spur gear W extends, the horizontal direction Y orthogonal to the X direction, and the vertical direction Z are shown. The arrow X1 in the X direction faces one side (the shooting side), and the arrow X2 in the X direction faces the other side (the illumination side). The Y-direction arrow Y1 faces one side of the Y-direction, and the Y-direction arrow Y2 faces the other side of the Y-direction. In addition, the arrow Z1 in the Z direction faces the vertical upward side, and the arrow Z2 in the Z direction faces the vertical downward side.

The imaging device 2 includes a holding part 21 that rotatably holds the workpiece W; a rotation driving part 22 that rotates the workpiece W held in the holding part 21 around a rotation axis AX1 extending in the horizontal direction; and an illumination part 23, which condenses and illuminates the inner peripheral surface Wb of the shaft hole Wa; and the imaging section 24, which photographs the region R1 condensed and illuminated by the illuminating section 23. In addition, the area R1 of the inner peripheral surface Wb that is condensed and illuminated by the illumination unit 23 and is locally imaged by the imaging unit 24 is referred to as the "photographed area R1".

As shown in FIG. 1, the holding portion 21 has rollers 211 and 212 that are rotatable around a rotation axis AX2 extending in the X direction. The rollers 211 and 212 are all made of a softer material than the spur gear W, such as rubber or resin. The one roller 211 is rotatably arranged while being in contact with the tooth top Wc of the spur gear W at a position lower than the rotation axis AX1 on the Y1 direction side with respect to the spur gear W. In addition, the other roller 212 is rotatably arranged while being in contact with the tooth top Wc of the spur gear W at a position lower than the rotation axis AX1 on the Y2 direction side with respect to the spur gear W. In this way, by the two rollers 211 and 212, the spur gear W is rotatably held from the lower side in a state where the axis AX3 of the shaft hole Wa is aligned with the rotation axis AX1. In addition, if the spur gear W is rotated around the rotation axis AX1 by the rotation drive unit 22 described below, the rollers 211 and 212 will follow the rotation of the spur gear W to rotate. In this way, the spur gear W is rotatably held by the holding portion 21 in the lateral posture.

As shown in FIG. 1, the rotation driving unit 22 has rollers 221 and 222 that are free to rotate around a rotation axis AX4 extending in the Z direction, and a motor 223 that drives the roller 222 to rotate. The rollers 221 and 222 are all made of a softer material than the spur gear W, such as rubber or resin, and are arranged so as to sandwich the side surface Wd of the spur gear W in the X direction. That is, the one roller 221 is rotatably arranged while being on the X1 direction side with respect to the spur gear W, and the lower side (Z2 direction side) of the side surface portion Wd is in contact with the side surface portion Wd of the spur gear W on the X1 direction side. In addition, the other roller 222 is rotatably arranged while being on the X2 direction side with respect to the spur gear W, and the lower side (Z2 direction side) of the side surface portion Wd is in contact with the side surface portion Wd on the X2 direction side of the spur gear W. In addition, the roller 222 is connected to a motor 223. Therefore, if the motor 223 is given a rotation command from the control device 3 of the entire control device, the motor 223 rotates and drives the roller 222 around the rotation axis AX4, and applies a frictional force in the Y2 direction to the side portion Wd of the spur gear W. The spur gear W is rotated in the direction of the arrow AR around the rotation axis AX1. In addition, in this embodiment, although the rollers 221 and 222 function as a driven roller and a driving roller to rotate the spur gear W, the motor 223 may be connected to the roller 221 so that the roller 221 serves as a driving roller. And function.

As shown in FIG. 1, the illuminating part 23 is arrange|positioned at the position away from the spur gear W held by the holding part 21 along the X2 direction. The lighting unit 23 has an LED (Light Emitting Diode) element (not shown). The illuminating unit 23 is arranged in a posture in which the light-emitting surface of the LED element faces the imaged region R1. In addition, if an illumination instruction from the control device 3 is received, the LED element will be lit to illuminate the illumination light diagonally downward from the X2 direction side to converge and illuminate the imaged area R1.

As shown in FIG. 1, the imaging section 24 is arranged at a position away from the spur gear W held by the holding section 21 in the X1 direction. The imaging unit 24 has a two-dimensional imaging element (not shown) such as a CCD (Charge Coupled Device) image sensor. The imaging unit 24 is arranged in a posture in which the imaging surface of the two-dimensional imaging element faces the imaged region R1, and locally images the inner peripheral surface Wb of the spur gear W rotating in the arrow direction AR. In more detail, the two-dimensional imaging element captures the captured region R1 that is condensed and illuminated by the illuminating unit 23 to obtain a partial image of the inner peripheral surface Wb of the spur gear W (symbol PI in FIG. 2). During the rotation of the spur gear W, the shooting of part of the image is repeated at a predetermined time interval (=T(2)-T(1)=T(3)-T(2)=...). At each shooting time point (time points T(1), T(2),... in Figure 2), the image data corresponding to a part of the image is sent from the camera unit 24 to the control device 3, and is stored in The image storage unit 31. Furthermore, in this embodiment, the spur gear W rotates one revolution around the rotation axis AX1 when the number of shots of the partial images reaches the predetermined number n (a natural number greater than 2), and n partial images PI will be It is accumulated in the image storage unit 31. That is, by obtaining n partial images PI, a full-periphery image of the inner peripheral surface Wb can be obtained. Of course, the number of partial images PI is not limited to n. It is also possible to obtain (n+1) or more partial images PI, and the entire circumference can be obtained by n consecutive partial images PI among them. image. In addition, it is also possible to obtain a full-circle image based on the partial image PI that exceeds one rotation by a well-known technique in the past.

The control device 3 is composed of a well-known CPU (Central Processing Unit) that executes logical operations, a ROM (Read Only Memory) that stores initial settings, etc., and temporarily stores various data in the operation of the device It is composed of RAM (Random Access Memory; Random Access Memory), etc., and functions as an image storage unit 31, an image synthesis unit 32, and an inspection unit 33. The image synthesizing unit 32 synthesizes the entire circumference image of the inner peripheral surface Wb based on the partial image PI stored in the image storage unit 31. In addition, the inspection unit 33 inspects the inner peripheral surface Wb of the spur gear W based on the entire peripheral image (symbol WI in FIG. 2).

FIG. 2 is a schematic diagram for explaining the acquisition of partial images and the acquisition of full-circumference images in the inspection device shown in FIG. 1. The vertical axis in the figure represents the time elapsed since the start of the rotation of the spur gear W by the rotation drive unit 22, and the imaging of the imaged area R1 by the imaging unit 24 is at each shooting time point T(1) , T(2), T(3),..., T(n), T(n+1), T(n+2),... are performed, and a partial image PI is obtained. In the present embodiment, as described above, the partial image PI is acquired n times during one rotation of the spur gear W, and is stored in the image storage unit 31. In addition, after n partial images PI are stored or immediately after two or more partial images PI are stored, the image synthesis unit 32 sequentially reads the partial images PI from the image storage unit 31, and The partial images PI that are adjacent to each other are connected to each other to synthesize a full-periphery image WI of the inner peripheral surface Wb. Here, the full-circle image WI can also be synthesized based on the partial images PI obtained at the shooting time points T(1), T(2), T(3), ..., T(n), for example, according to The partial images PI obtained at the shooting time points T(2), T(3), ..., T(n), T(n+1) are combined into a full-circle image WI.

The inspection unit 33 compares the entire circumference image WI acquired as described above with the reference image to inspect whether there are defects such as scratches or defects on the inner circumferential surface Wb.

As described above, in this embodiment, the spur gear W is rotated in a horizontal posture in which the axis AX3 of the shaft hole Wa coincides with the rotation axis AX1 of the spur gear W, and the imaging unit 24 is used to capture images by the illumination unit 23. The spotlighted area R1. Therefore, it is not necessary to change the component parts of the imaging device 2 in order to photograph spur gears W or workpieces other than the spur gears of different shapes or sizes, and for a variety of workpieces, it is possible to photograph the tube set on each workpiece with higher versatility Shaped inner peripheral surface.

As described above, in this embodiment, the illuminating unit 23 and the imaging unit 24 respectively correspond to an example of the "first illuminating unit" and the "first imaging unit" of the present invention. The X direction, the X1 direction side, and the X2 direction side correspond to the "horizontal direction", "one side of the workpiece", and "the other side of the workpiece" in the present invention, respectively. The partial image PI corresponds to an example of the "first partial image" in the present invention.

In addition, the present invention is not limited to the above-mentioned embodiments, and various changes other than those described above can be made without departing from the gist. For example, in the above-mentioned embodiment, as shown in FIG. 1, the imaged area R1 is set to the lowermost side of the inner peripheral surface Wb. That is, although the illuminating light is irradiated from diagonally above to the captured region R1 and the spur gear W is partially captured by the imaging section 24 from diagonally above the captured region R1 to capture the partial image PI, the position of the captured region R1 is not It is limited to the lowest part of the inner peripheral surface Wb. For example, the illuminating light may be irradiated from the obliquely downward direction of the photographed area R1, and the spur gear W may be partially photographed by the imaging unit 24 from the obliquely downward direction of the photographed area R1 to photograph the partial image PI.

In addition, in the above-described embodiment, the illuminating unit 23 condenses and illuminates the imaged region R1, but it may be configured to illuminate the entire inner peripheral surface Wb.

In addition, in the above-described embodiment, only the inner peripheral surface Wb is imaged and inspected, but the outer surface of the spur gear W may be imaged and inspected simultaneously with the inner peripheral surface Wb (second embodiment).

Fig. 3 is a diagram showing the overall configuration of an inspection device equipped with a second embodiment of the imaging device of the present invention. The imaging device 2 of the second embodiment differs greatly from the first embodiment in that in order to image the outer surface of the spur gear W, a second illuminating unit 25 and three of the "second imaging unit" of the present invention are added. The other components of the imaging units 26-28 are basically the same as those of the first embodiment.

The second illuminating unit 25 illuminates the vicinity of the upper end of the spur gear W. Then, the imaging units 26 to 28 respectively take images of the area R2 illuminated by the second illuminating unit 25 from the Z1 direction side, the diagonally upward side, and the X1 direction side. That is, as shown in FIG. 3, the imaging unit 26 is arranged at a position directly above the spur gear W rotated by the rotation driving unit 22, and the tooth top Wc in the region R2 is captured to obtain a partial image of the tooth top Wc. In addition, the imaging unit 28 is arranged on the X1 direction side of the region R2, and the side surface Wd of the region R2 is captured to obtain a partial image of the side surface Wd. In addition, the imaging unit 27 is arranged between the imaging units 26 and 28, and captures the area R2 from an obliquely above and captures the vicinity of the tooth root of the spur gear W rotated by the rotation drive unit 22 to obtain a partial image of the vicinity of the tooth root.

If the spur gear W is rotated by the rotation drive unit 22, as in the first embodiment, the image data corresponding to the partial image of the inner circumferential surface Wb will be sent from the imaging unit 24 to the The control device 3 is stored in the image storage unit 31. And at the same time, the image data corresponding to the partial image of the tooth top Wc, the image data corresponding to the partial image near the tooth root, and the image data corresponding to the partial image of the lateral part Wd, at each shooting time The points are respectively sent from the imaging units 26 to 28 to the control device 3 and stored in the image storage unit 31.

The image synthesizing unit 32 sequentially reads out partial images from the image storage unit 31, and synthesizes the entire peripheral images of the inner peripheral surface Wb, the tooth top Wc, the vicinity of the tooth root, and the side surface Wd. Then, the inspection unit 33 compares the entire circumference image obtained as described above with the reference image to inspect whether there are defects such as scratches or defects on the inner peripheral surface Wb or the outer surface of the spur gear W.

As described above, in the second embodiment, a partial image of the inner peripheral surface Wb is acquired as the "first partial image" of the present invention, and partial images of the tooth top Wc, the vicinity of the tooth root, and the side surface Wd are obtained The image is acquired as the "Second Part Image" of the present invention. Therefore, the outer surface of the spur gear W can be photographed simultaneously with the inner peripheral surface Wb of the shaft hole Wa of the spur gear W to obtain images effective for inspection, and the spur gear W can be inspected comprehensively based on these images. Furthermore, in the second embodiment, as an example of a workpiece, in order to inspect the outer surface of the spur gear W, three imaging units 26-28 are arranged in the vertical direction, diagonally above, and lateral direction, respectively, but the outer surface is used for imaging The number or arrangement of the imaging unit is not limited to this, but can be changed appropriately according to the type of workpiece.

In addition, in the above embodiment, the tooth top Wc of the spur gear W is supported by rollers 211 and 212, and the spur gear W can be rotated freely in a lateral posture in which the axis AX3 of the shaft hole Wa coincides with the rotation axis AX1 of the spur gear W However, the structure of the holding portion 21 is not limited to this. For example, the inner peripheral surface Wb of the shaft hole Wa may be joined to one or a plurality of rollers, and the spur gear W may be rotatably suspended and held.

In addition, in the above-mentioned embodiment, although the frictional force in the Y2 direction is applied to the side surface portion Wd of the spur gear W to rotate the spur gear W, the configuration of the rotation drive unit 22 is not limited to this. For example, at least one of the rollers 211 and 212 constituting the holding portion 21 may be given a rotational driving force to rotate the spur gear W.

In addition, in the above-mentioned embodiment, although the inner peripheral surface Wb is partially illuminated by the illuminating unit 23, it may be configured to image the inner peripheral surface Wb in a state where the entire spur gear W is uniformly illuminated.

In addition, in the above-mentioned embodiment, although the spur gear W is taken as an example of the "workpiece" of the present invention, the spur gear W is photographed and inspected, but the applicable object of the present invention is not limited to this, for example, a helical gear All parts of cylindrical parts such as helical gear, screw gear, double helical (herringbone) gear, internal gear, etc., or bushings are also included in the "workpiece" of the present invention.

Above, although the invention has been described based on specific embodiments, the description is not intended to be interpreted in a limited sense. If referring to the description of the invention, as with other embodiments of the present invention, a person having ordinary knowledge in the technical field to which the present invention pertains can clearly know various modifications of the disclosed embodiments. Therefore, the scope of the attached patent application may include the modification or embodiment within the scope that does not deviate from the essential scope of the invention.

The present invention can be applied to all imaging techniques for photographing workpieces with cylindrical parts and all inspection techniques for inspecting cylindrical inner peripheral surfaces.

1: Inspection device 2: camera device 3: control device 21: Holding part 22: Rotary drive unit 23: (1st) Lighting Department 24: (1st) Camera Department 25: The second lighting department 26～28: (Second) Camera Department 31: Image storage section 32: Image Synthesis Department 33: Inspection Department 211,212,221,222: Roll 223: Motor AX1, AX2, AX4: Rotation axis AX3: axis AR: arrow direction PI: partial image R1: Area being photographed W: Spur gear (workpiece) Wa: Shaft hole (tubular part) Wb: (cylindrical) inner peripheral surface Wc: top of tooth Wd: side WI: Full week image X, X1, X2, Y, Y1, Y2: horizontal direction Z, Z1, Z2: vertical direction

Fig. 1 is a diagram showing the overall configuration of an inspection device equipped with a first embodiment of the imaging device of the present invention. FIG. 2 is a schematic diagram for explaining the acquisition of partial images and the acquisition of full-circumference images in the inspection device shown in FIG. 1. Fig. 3 is a diagram showing the overall configuration of an inspection device equipped with a second embodiment of the imaging device of the present invention.

1: Inspection device

2: camera device

3: control device

21: Holding part

22: Rotary drive unit

23: Lighting Department

24: Camera Department

31: Image storage section

32: Image Synthesis Department

33: Inspection Department

211,212,221,222: Roll

223: Motor

AX1, AX2, AX4: Rotation axis

AX3: axis

AR: arrow direction

R1: Area being photographed

W: Spur gear (workpiece)

Wa: Shaft hole (tubular part)

Wb: (cylindrical) inner peripheral surface

Wc: top of tooth

Wd: side

X, X1, X2, Y, Y1, Y2: horizontal direction

Z, Z1, Z2: vertical direction

Claims (6)

An imaging device that photographs the cylindrical inner peripheral surface of a cylindrical part that is penetrated with respect to a workpiece; it is characterized in that it is provided with: A holding portion that rotatably holds the workpiece around the rotating shaft in a state that the axis of the cylindrical portion is aligned with the rotating shaft extending in the horizontal direction; A rotation driving part that rotates the workpiece held in the holding part about the rotation axis; A first illuminating part that illuminates the cylindrical inner peripheral surface rotated by the rotation driving part; and A first imaging unit for partially imaging the cylindrical inner peripheral surface from an oblique direction from a position away from the workpiece in the horizontal direction on the workpiece rotated by the rotation drive unit to obtain the tube The first part of the image of the inner peripheral surface of the shape; The entire circumference image of the cylindrical inner peripheral surface is acquired by acquiring a plurality of the first partial images by the first imaging unit while the workpiece is rotating at least one revolution around the rotation axis. Such as the camera device of claim 1, in which, The first illuminating unit partially illuminates the imaged area on the cylindrical inner peripheral surface where the first partial image is obtained from the other side of the workpiece held by the holding unit in the horizontal direction. The spotlighting. Such as the camera device of claim 1 or 2, which has: A second illuminating part that illuminates the outer surface of the workpiece rotated by the rotation driving part; and A second imaging unit that partially captures the workpiece from the outer side of the workpiece rotated by the rotation drive unit to obtain a second partial image of the outer surface; The image of the outer surface is acquired by acquiring a plurality of the second partial images by the second imaging unit while the workpiece is rotating at least one revolution around the rotation axis. Such as the camera device of claim 3, in which, The acquisition of the first partial image by the first imaging unit is performed simultaneously with the acquisition of the second partial image by the second imaging unit. A photographing method that photographs a cylindrical inner peripheral surface of a cylindrical part that is penetrated with respect to a workpiece; and is characterized in that it has: The step of rotating the workpiece around the rotating shaft in a state where the axis of the cylindrical part is aligned with the rotating shaft extending in the horizontal direction; While the workpiece rotates at least one revolution about the rotation axis, while illuminating the cylindrical inner peripheral surface of the workpiece rotating about the rotation axis, it is separated from a position on one side of the workpiece in the horizontal direction. A step of photographing the cylindrical inner peripheral surface from an oblique direction to obtain a plurality of first partial images of the cylindrical inner peripheral surface; and A step of obtaining a full-periphery image of the cylindrical inner peripheral surface based on the plurality of first partial images. An inspection device, characterized in that it is provided with: The camera device described in any one of Claims 1 to 4; and An inspection unit that inspects the cylindrical inner peripheral surface based on the plurality of first partial images acquired by the imaging device.

Images