Imaging method

Abstract

To provide an imaging method capable of quickly adjusting a camera position when imaging an object having multiple unit parts in the same shape.SOLUTION: An imaging method is used to image an object having multiple unit parts in the same shape, and has a step of setting multiple imaging points for an optional representative unit part included in multiple unit parts on the basis of design shape information of the object, a step of generating a camera position focusing an optional reference imaging point included in multiple imaging points and a camera position for all the other imaging points set on a representative unit part on the basis of design shape information of an object, and generating an imaging route in the representative unit part, and a step of generating an imaging route for unit parts other than the representative unit part on the basis of an imaging route in a representative unit part and design shape information of an object, and moves a camera 2 on the basis of the generated imaging route and images the object.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an imaging method.

Background Art

[0002] One method for detecting defects present in an object to be inspected, such as parts and members, is an inspection method of imaging the object to be inspected using a camera. In this inspection method using a camera, high inspection accuracy can be achieved by focusing on the object to be inspected and imaging it. However, depending on the shape of the subject to be inspected and the installation state on the inspection apparatus, it may be difficult to focus on the subject, resulting in a blurred captured image and a decrease in inspection accuracy. For this reason, in the inspection method using a camera, it is important to adjust the position, angle, and focus of the camera (hereinafter referred to as the camera position), and this is appropriately performed. A method for accurately adjusting the camera position has been proposed in Patent Document 1. Patent Document 1 discloses a method using a calibrator capable of capturing images with different luminance distributions. In this method, a calibrator is installed on the camera side of the subject surface, and the camera position is adjusted based on the luminance distribution of the image obtained by imaging the calibration surface with the camera.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Regarding the method for adjusting the camera position disclosed in Patent Document 1, the inventors have found the following problems. In the method for adjusting the camera position disclosed in Patent Document 1, it is necessary to install a calibrator on the camera side of the subject surface. Therefore, when the shape of the subject is complex, the installation state becomes unstable. Furthermore, when it is desired to image a plurality of locations on one subject, it is necessary to reset the camera position every time the imaging location is changed, which takes a huge amount of time for the work.

[0005] The present invention has been made to solve such problems, and provides an imaging method capable of adjusting the camera position in a short time when imaging a subject having a plurality of unit parts of the same shape.

Means for Solving the Problems

[0006] The imaging method according to the present invention is an imaging method for imaging a subject having a plurality of unit parts of the same shape, and based on the design shape information of the subject, for any representative unit part included in the plurality of unit parts, setting a plurality of imaging points, a camera position in focus with respect to any reference imaging point included in the plurality of imaging points, and based on the design shape information of the subject, generating a camera position for all other imaging points set on the representative unit part, and generating an imaging path in the representative unit part, and based on the imaging path in the representative unit part and the design shape information of the subject, generating an imaging path for unit parts other than the representative unit part, and moving the camera based on the generated imaging path to image the subject.

[0007] Also, in the step of setting the plurality of imaging points, it is preferable to set inflection points on the path along the outer shape of the unit part as the imaging points. By performing such processing, in particular, an imaging image focused near the outer shape can be obtained, and inspection near the outer shape can be performed precisely.

[0008] Further, it is preferable to move the camera at a certain speed or more based on the generated imaging path, image the subject multiple times, and generate an in-focus image for the plurality of imaging points by stacking and synthesizing the captured images. When moving the camera at a certain speed or more, positional deviation is likely to occur at the inflection point, so the technical significance of using this inflection point as an imaging point is high.

[0009] Further, after the step of generating the imaging path for the representative unit site, it is preferable to include a step of correcting the camera position for all imaging points set on the representative unit site, and based on the imaging path reflecting the correction, execute the step of generating the imaging path for the other unit sites. Since the camera position is corrected at the imaging points set at the inflection point where positional deviation is likely to occur, the camera position can be corrected more effectively.

[0010] Further, it is preferable that the subject is a tooth cutting tool and the unit site is the cutting edge of the tooth cutting tool.

Advantages of the Invention

[0011] According to the present invention, when imaging a subject having a plurality of unit sites of the same shape, it is possible to provide an imaging method capable of adjusting the camera position in a short time.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying Out the Invention

[0013] Embodiment 1 Hereinafter, with reference to the drawings, the imaging method according to Embodiment 1 will be described. The imaging method according to this embodiment images a subject having a plurality of unit parts of the same shape. More specifically, in this imaging method, the camera moves to a camera position that focuses on the unit part and images the subject. In this embodiment, the subject is a tooth cutting tool 1, and each cutting edge 11 in the tooth cutting tool 1 is imaged. Note that the subject is not limited to the tooth cutting tool, and any subject having a plurality of unit parts of the same shape may be used.

[0014] <Configuration of Imaging Device> First, with reference to FIG. 1, the configuration of an imaging device (imaging system) for realizing the imaging method according to Embodiment 1 will be described. As shown in FIG. 1, the imaging device 100 includes a camera 2, a robot arm 3, a control device 4, and a holding unit 5. The imaging device 100 is a robot-type imaging device including an articulated robot arm 3. In this embodiment, the cutting edge 11 of the tooth cutting tool 1 is imaged using the imaging device 100.

[0015] Here, as shown in FIG. 2, the tooth cutting tool 1 as the subject includes a plurality of cutting edges 11 and grooves 12 for forming the cutting edges 11. Further, the cutting edge 11 includes a tooth surface 13 and a rake face 14. Examples of the type of the tooth cutting tool 1 include a skiving cutter, a pinion cutter, a shaving cutter, and a hob. In this embodiment, the tooth cutting tool 1 is a hob. Further, the imaging device 100 images the tooth surface 13 side of the cutting edge 11.

[0016] The camera 2 is an imaging means for imaging the subject, and is constituted by an imaging element such as a CCD image sensor or a CMOS image sensor, for example. The camera 2 is provided on the robot arm 3. Then, the camera 2 moves by the movement of the robot arm 3. Further, the camera 2 transmits the captured image to the control device 4.

[0017] The robot arm 3 is provided with the camera 2 and changes the position and orientation of the camera 2 according to the command of the control device 4. Specifically, the control device 4 commands the imaging path to the robot arm 3, and the robot arm 3 moves the camera 2 based on the imaging path. In a typical example, the robot arm 3 continuously moves the camera 2 at a certain speed or higher without stopping at the imaging point. At this time, the robot arm 3 may move the camera 2 at a basically constant speed except at the start and stop of the operation. In the present embodiment, as shown in FIG. 1, in order to change the relative positional relationship between the camera 2 and the tooth cutting tool 1, the imaging device 100 has a configuration in which the position of the tooth cutting tool 1 is fixed and the camera 2 is moved by the robot arm 3, but is not limited thereto. For example, the imaging device 100 may have a configuration in which the position of the camera 2 is fixed and the tooth cutting tool 1 is held by the robot arm 3 so that the position and angle of the held tooth cutting tool 1 can be changed.

[0018] The holding unit 5 is for fixing the tooth cutting tool 1 that is the imaging object. The holding unit 5 includes, for example, a motor, various gears, and a motor control mechanism, and may appropriately rotate the tooth cutting tool 1 in accordance with imaging by the camera 2.

[0019] The control device 4 is a control means that moves the robot arm 3 to move the camera 2 based on the imaging path to image the subject, receives the captured image from the camera 2, and performs stacked synthesis of the images. In the present embodiment, the control device 4 moves the camera 2 to a predetermined camera position in order to capture an image focused on the tooth surface 13 of the cutting edge 11.

[0020] Here, the camera position with respect to the unit part will be described. When imaging each unit part in a subject having a plurality of unit parts of the same shape, it may be difficult to find a camera position that is in focus for the entire unit part. For example, in the present embodiment, since the tooth cutting tool 1 is a hob, due to the structure of the hob, it is difficult for the imaging device 100 to direct the camera directly at the tooth surface 13 of the cutting edge 11 which is the unit part. Therefore, the imaging device 100 needs to direct the camera 2 obliquely with respect to the tooth surface 13, and it is difficult to capture an image that is in focus for the entire tooth surface 13.

[0021] Therefore, in the present embodiment, the control device 4 sets a plurality of imaging points on the tooth surface 13 of the cutting edge 11 which is the unit part, and generates a camera position that is in focus for each imaging point. Then, the control device 4 generates an imaging path based on the camera positions of each imaging point, moves the camera 2 based on the generated imaging path, and images the tooth surface 13 of the cutting edge 11. The camera 2 performs imaging a plurality of times on the imaging path, and transmits the plurality of captured images to the control device 4. Then, the control device 4 generates an image that is in focus for the plurality of imaging points by stacking and synthesizing the plurality of images received from the camera 2.

[0022] Next, with reference to FIG. 3, the configuration of the control device 4 will be described. The control device 4 includes an imaging path calculation unit 41, a movement operation control unit 42, and an imaging image synthesis unit 43. The control device 4 is configured by, for example, a CPU (Central Processing Unit) and various memories. In the present embodiment, the imaging path calculation unit 41, the movement operation control unit 42, and the imaging image synthesis unit 43 are provided in the same control device 4, but may be provided in separate control devices 4 respectively.

[0023] The imaging path calculation unit 41 generates an imaging path and outputs the imaging path to the movement operation control unit 42. First, the imaging path calculation unit 41 selects an arbitrary unit part (hereinafter referred to as a representative unit part) included in a plurality of unit parts of the subject, and sets a plurality of imaging points on the representative unit part based on the design shape information of the subject. The imaging path calculation unit 41 may, for example, extract the feature points of the outer shape of the unit part and use those feature points as the imaging points. From the viewpoint of ease of extraction as feature points, the imaging path calculation unit 41 preferably sets the inflection points on the path along the outer shape of the unit part as the imaging points. The design shape information is, for example, CAD (computer aided design) data, but is not limited thereto, and may be non-CAD data that has not been created by CAD.

[0024] Then, the user selects an arbitrary imaging point (hereinafter referred to as a reference imaging point) from the plurality of imaging points, inputs the camera position that is in focus with respect to the reference imaging point to the imaging path calculation unit 41, and executes teaching. The imaging path calculation unit 41 generates the camera positions for all the other imaging points set on the representative unit part based on the camera position that is in focus with respect to the reference imaging point and the design shape information of the subject. Then, the imaging path calculation unit 41 generates an imaging path connecting the camera positions for all the imaging points in the representative unit part. Next, the imaging path calculation unit 41 generates an imaging path for unit parts other than the representative unit part based on the imaging path in the representative unit part and the design shape information of the subject.

[0025] In addition, in this embodiment, in order for the control device 4 to stack and synthesize images, the camera 2 performs imaging a plurality of times on the imaging path. Therefore, if the change in the moving speed on the imaging path of the camera 2 is large, the captured images will not be stable. Therefore, it is preferable that the camera moves at a constant speed or higher without stopping on the imaging path. However, when the camera 2 moves at a constant speed or higher, there is a possibility that the actual movement path of the camera 2 due to moving the robot arm 3 near the imaging point may deviate from the imaging path generated by the imaging path calculation unit 41. Therefore, it is preferable that the imaging path calculation unit 41 generates an imaging path in consideration of the deviation from the movement path of the camera 2 due to the movement of the robot arm 3. For example, it is advisable to set in advance the correction amount of the camera position for each imaging point and use the correction amount to generate the imaging path.

[0026] Based on the imaging path output input by the imaging path calculation unit 41, the movement operation control unit 42 moves the robot arm 3 to control the position, posture, and moving speed of the camera 2.

[0027] The captured image synthesis unit 43 generates an image in focus for a plurality of imaging points by stacking and synthesizing a plurality of images received from the camera 2. Then, the generated image is output to a notification unit such as a display (not shown).

[0028] <Imaging method> Subsequently, the imaging method according to Embodiment 1 of the present invention will be described. FIG. 4 is a flowchart of the imaging method according to Embodiment 1 of the present invention. In this embodiment, the subject is the tooth cutting tool 1, and each cutting edge 11 of the tooth cutting tool 1 is imaged. However, the subject is not limited to the tooth cutting tool, and any subject having a plurality of unit parts of the same shape may be used.

[0029] First, the user selects an arbitrary imaging point (hereinafter referred to as the reference imaging point) from a plurality of imaging points on the tooth surface 13 of the cutting edge (hereinafter referred to as the representative cutting edge), which is the representative unit part, and inputs the camera position in focus with respect to the reference imaging point to the imaging path calculation unit 41 to execute teaching (step S101).

[0030] Before this step S101, the imaging path calculation unit 41 sets a plurality of imaging points on the tooth surface 13 of the representative cutting edge. For example, as shown in FIG. 5, the imaging path calculation unit 41 sets a plurality of imaging points from P1 to P6 on the tooth surface 13 of the representative cutting edge. These plurality of imaging points are generated by the imaging path calculation unit 41 based on the design shape information of the tooth cutting tool 1 that is the subject, and the inflection points on the path along the outer shape of the unit part are set as the imaging points. The user selects, as a reference imaging point, an imaging point such as P2 that is easy to focus on from the plurality of imaging points generated by the imaging path calculation unit 41. Then, the user adjusts the camera position that is in focus with respect to the reference imaging point (P2) and inputs this camera position to the imaging path calculation unit 41 to execute teaching.

[0031] Next, the imaging path calculation unit 41 calculates the imaging path for the representative cutting edge (step S102). The imaging path calculation unit 41 generates camera positions for all other imaging points (P1, P3 to P6) set on the tooth surface 13 of the representative cutting edge based on the camera position for the reference imaging point (P2) input in step S101 and the design shape information of the subject. Then, the imaging path calculation unit 41 generates an imaging path for the representative cutting edge by connecting the camera positions for all the imaging points (P1 to P6) set on the tooth surface 13 of the representative cutting edge.

[0032] The imaging path generated by the imaging path calculation unit 41 may deviate from the actual movement path of the camera 2 by moving the robot arm 3. Therefore, it is preferable that the imaging path calculation unit 41 generates an imaging path considering the deviation from the movement path of the camera 2 due to the movement of the robot arm 3. In the present embodiment, the correction amount of the camera position for each imaging point is set in advance, and the imaging path calculation unit 41 generates an imaging path using the correction amount.

[0033] Next, the imaging path calculation unit 41 calculates the imaging path for the cutting edge 11 other than the representative cutting edge (step S103). The imaging path calculation unit 41 generates the imaging path for the cutting edge 11 other than the representative cutting edge based on the imaging path for the representative cutting edge generated in step S102 and the design shape information of the tooth cutting tool 1. In the present embodiment, since the imaging target is the tooth cutting tool 1, the imaging path calculation unit 41 extracts, from the design shape information, for example, the pitch, lead angle, number of teeth, overall length, etc. of the tooth cutting tool. If the imaging path was generated using the correction amount in step S102, the imaging path calculation unit 41 generates the imaging path for the cutting edge 11 other than the representative cutting edge based on the imaging path reflecting the correction for the representative cutting edge and the design shape information of the tooth cutting tool 1.

[0034] Next, the imaging path calculation unit 41 inputs the imaging paths for each cutting edge 11 generated in step S102 and this step S103 to the movement operation control unit 42 (step S104).

[0035] Next, the movement operation control unit 42 controls the robot arm 3 to move the camera 2 based on the imaging path output input from the imaging path calculation unit 41, and the camera 2 images the representative cutting edge (step S105). The camera 2 performs imaging a plurality of times on the imaging path of the representative cutting edge, and transmits the captured images to the imaging image synthesis unit 43.

[0036] Next, the imaging image synthesis unit 43 generates a representative cutting edge image from the images received from the camera 2, and the user determines whether the focus of the image is in focus (step S106). The imaging image synthesis unit 43 stacks and synthesizes the plurality of images received from the camera 2, and generates an image of the representative cutting edge that is in focus for a plurality of imaging points (from P1 to P6). Then, the imaging image synthesis unit 43 outputs the generated image of the representative cutting edge to a notification unit such as a display (not shown). The user determines whether the image of the representative cutting edge is in focus for a plurality of imaging points (from P1 to P6).

[0037] In step S106, when it is determined that the focus is not on a plurality of imaging points (P1 to P6), the imaging path calculation unit 41 adjusts the correction amount of the camera position for each imaging point (step S107). After adjusting the correction amount, the imaging path calculation unit 41 executes imaging path generation from step S102.

[0038] In step S106, when it is determined that the focus is on a plurality of imaging points (P1 to P6), the movement operation control unit 42 controls the robot arm 3 to move the camera 2 based on the imaging path, and the camera 2 images the cutting edge 11 other than the representative cutting edge (step S108). The camera 2 performs imaging a plurality of times on the imaging path and transmits the captured images to the captured image synthesis unit 43. Next, the plurality of images received from the camera 2 are stacked and synthesized to generate an image in focus for a plurality of imaging points (P1 to P6) on each cutting edge 11. Then, the captured image synthesis unit 43 outputs the generated image of the representative cutting edge to a notification unit such as a display (not shown).

[0039] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit thereof.

[0040] In the present embodiment, the step of generating the imaging path for the cutting edge 11 other than the representative cutting edge in step S103 is executed after the step of generating the imaging path for the representative cutting edge in step S102, but is not limited thereto. For example, the step of generating the imaging path for the cutting edge 11 other than the representative cutting edge in step S103 may be executed after the step of checking whether the focus of the representative cutting edge image is in step S106.

[0041] Also, in the present disclosure, it is also possible to cause the control device 4 to execute part or all of the implementation and determination by the user. For example, the adjustment of the camera position in focus on the reference imaging point in step S106 and the determination of whether the image is in focus in step S106 are executed by the user, but these may be executed by the control device 4.

Explanation of Symbols

[0042] 1 Tooth Cutting Tool 2 Camera 3 Robot Arm 4 Control Device 5 Holding Part 11 Cutting Edge 12 Groove 13 Tooth Surface 14 Rake Face 41 Imaging Path Calculation Unit 42 Movement Operation Control Unit 43 Captured Image Composition Unit 100 Imaging Device

Claims

1. An imaging method for imaging a subject having a plurality of unit parts of the same shape, comprising: Based on the design shape information of the subject, for any representative unit part included in the plurality of unit parts, setting a plurality of imaging points; Based on a camera position in focus with respect to any reference imaging point included in the plurality of imaging points and the design shape information of the subject, generating camera positions for all other imaging points set on the representative unit part, and generating an imaging path in the representative unit part; Based on the imaging path in the representative unit part and the design shape information of the subject, generating an imaging path for a unit part other than the representative unit part; An imaging method of moving a camera based on the generated imaging path to image the subject.

2. In the step of setting the plurality of imaging points, inflection points on a path along the outer shape of the unit part are set as the imaging points. The imaging method according to Claim 1.

3. Moving the camera at a certain speed or higher based on the generated imaging path, imaging the subject a plurality of times, and generating an image in focus for the plurality of imaging points by stacking and synthesizing the captured images. The imaging method according to Claim 1 or 2.

4. After the step of generating the imaging path in the representative unit part, Comprising a step of correcting the camera positions for all imaging points set on the representative unit part, Executing a step of generating an imaging path for the other unit part based on the imaging path reflecting the correction. The imaging method according to Claim 3.

5. The subject is a tooth cutting tool, and the unit part is a cutting edge of the tooth cutting tool. The imaging method according to Claim 4.

Images