Calibration fixture, calibration method and measurement system for measurement device for measuring three-dimensional geometry

Abstract

The invention provides a calibration fixture, a calibration method and a measurement system of a measurement device for measuring a three-dimensional geometry. A calibration jig (300) for calibrating a measurement apparatus (10) for measuring a three-dimensional geometry of a measurement object and comprising a plurality of camera sections (132) for shooting the measurement object, the calibration jig comprising: a plurality of elements (31) to be measured; and a frame portion (40) to which a plurality of elements (31) to be measured are attached, in which the plurality of elements (31) to be measured each comprise: a main body portion (32) having a predetermined shape; and a plurality of tag sections (33) provided on the main body section (32), on each of which an identification code (36) for identifying the element (31) to be measured is shown.

Description

Technical Field

[0001] The present disclosure relates to a calibration fixture, a calibration method and a measurement system for a measuring device for measuring three-dimensional geometric shapes. Background Art

[0002] The following measuring device is known: the measuring device includes multiple cameras, and measures the three-dimensional geometry of the measuring object in a non-contact manner based on the results obtained by photographing the measuring object from multiple directions (for example, refer to patent document 1, Japanese patent table 2019-507885). In this measuring device, the device is calibrated by photographing the same calibration fixture with multiple cameras or by photographing a calibration fixture with known dimensions with multiple cameras. In addition, there is a known alignment method called pairwise alignment (for example, see non-patent document 1, Toru Tamaki, "Pose Estimation and Rotation matrix", IEICE Technical Report, Institute of Electronics, Information and Communications Engineers, 2009, SIP2009-48 and SIS2009-23, pages 59 to 64). Summary of the invention

[0003] Problem that the invention aims to solve

[0004] However, since the plurality of camera devices photograph the calibration jig from different angles, it is difficult to identify from the photographing results which part of the calibration jig is being photographed by each camera device. In addition, in the case of a measuring device for measuring the three-dimensional geometry of a large measuring object or a measuring device for measuring the three-dimensional geometry of a complex measuring object, it is difficult for the plurality of camera devices to photograph the same calibration jig because the plurality of camera devices are arranged at various positions in this case.

[0005] The present disclosure focuses on these points with the aim of easily calibrating a measuring device for measuring the three-dimensional geometry of a measurement object.

[0006] Solutions for solving problems

[0007] A first aspect of the present disclosure provides a calibration fixture for calibrating a measuring device, the measuring device being used to measure a three-dimensional geometric shape of a measuring object and comprising a plurality of camera parts for photographing the measuring object, the calibration fixture comprising: a plurality of elements to be measured; and a frame part to which the plurality of elements to be measured are attached, wherein the plurality of elements to be measured each comprises: a main body part having a predetermined shape; and a plurality of label parts arranged on the main body part, wherein an identification code for identifying the element to be measured is shown on each label part.

[0008] The label portion may further include an identification code common to the plurality of components to be measured and used to identify the label portion.

[0009] The identification code may be composed of a combination of basic components of a predetermined first shape, and the recognition code may be composed of a combination of basic components of a predetermined second shape having a size different from that of the first shape.

[0010] The identification code may be composed of a combination of basic components of a predetermined first shape, and the recognition code may include basic components of a predetermined color different from the color of the basic components of the first shape.

[0011] The identification code may be composed of a combination of basic components of a predetermined first shape, and the recognition code may include basic components of a predetermined color different from the color of the basic components of the first shape.

[0012] The identification code and the recognition code may be composed of a barcode, and a minimum line width of the barcode of the identification code may be different from a minimum line width of the barcode of the recognition code.

[0013] The minimum line width of the barcode of the identification code may be greater than the minimum line width of the barcode of the recognition code.

[0014] Each of the plurality of elements to be measured may further include: a belt-shaped plate member provided around the main body portion, and the plurality of label portions may be provided on the plate member.

[0015] The calibration fixture may further include: a frame moving portion for moving the frame portion together with the plurality of elements to be measured.

[0016] The frame portion may have a spherical or elliptical shape, and the plurality of elements to be measured may each be disposed on a spherical or elliptical surface of the frame portion.

[0017] A second aspect of the present disclosure provides a calibration method for calibrating a measuring device using a calibration fixture, the measuring device being used to measure the three-dimensional geometric shape of a measuring object and comprising a plurality of camera parts for photographing the measuring object, wherein the calibration fixture comprises a plurality of elements to be measured, each of the plurality of elements to be measured comprising: a main body having a predetermined shape; and a plurality of label parts arranged on the main body, wherein an identification code for identifying the elements to be measured is shown on each label part, and the calibration method comprises: a first photographing step for photographing the calibration fixture using the first camera part in such a manner that a portion of the first elements to be measured among the plurality of elements to be measured are included in the field of view of the first camera part, and in such a manner that the first elements to be measured are in the field of view of the first camera part. The calibration fixture is photographed by the second imaging unit in such a manner that a part of the second element to be measured that is different from the first element to be measured photographed by the first imaging unit is included in the field of view of a second imaging unit that is different from the first imaging unit; a step for identifying the element to be measured, the step comprising: identifying the first element to be measured by analyzing a label portion of the element to be measured from the image photographed by the first imaging unit, and identifying the second element to be measured by analyzing the label portion of the element to be measured from the image photographed by the second imaging unit; and a step for identifying calibration parameters for calibrating the first imaging unit and the second imaging unit according to a positional relationship between the identified first element to be measured and the identified second element to be measured.

[0018] The step for identifying the element to be measured may include: extracting the image data ID of the first element to be measured from the image captured by the first camera unit; calculating the transformation matrix TI using the ideal image data IID of the first element to be measured, so that the calculation result of IID×TI becomes the image data ID of the first element to be measured; and calculating the inverse matrix TI of the transformation matrix TI. -1 By multiplying the image data ID of the first element to be measured by the calculated inverse matrix TI -1 to perform image conversion; and read an identification code of a label portion provided in the first component to be measured from data obtained by converting the image data ID.

[0019] The calibration method may further include: a second imaging step for photographing the first element to be measured using the first imaging unit and photographing the second element to be measured using the second imaging unit after the calibration fixture is moved in a predetermined first direction after the first imaging step; a third imaging step for photographing the first element to be measured using the first imaging unit and photographing the second element to be measured using the second imaging unit after the calibration fixture is moved in a predetermined second direction different from the first direction after the second imaging step; a fourth imaging step for photographing the first element to be measured using the first imaging unit and photographing the second element to be measured using the second imaging unit; a fifth imaging step for photographing the first element to be measured using the first imaging unit and photographing the second element to be measured using the second imaging unit after the calibration fixture is rotated around an axis oriented in a predetermined third direction after the fourth imaging step; and a sixth imaging step for photographing the first element to be measured using the first imaging unit and photographing the second element to be measured using the second imaging unit after the calibration fixture is rotated around an axis oriented in a predetermined fourth direction different from the third direction after the fifth imaging step. photographing the first element to be measured and photographing the second element to be measured using the second imaging unit; and identifying a first coordinate position in a plurality of images photographed by the first imaging unit and identifying a second coordinate position in a plurality of images photographed by the second imaging unit, the first coordinate position being used to indicate a position of the first element to be measured in a first coordinate system based on a field of view of the first imaging unit, and the second coordinate position being used to indicate a position of the second element to be measured in a second coordinate system based on a field of view of the second imaging unit, wherein the step of identifying the calibration parameter comprises: identifying a first rotation matrix for rotating the first coordinate system and a second rotation matrix for rotating the second coordinate system to perform coordinate transformation, so that the direction in which the first coordinate position moves and the direction in which the second coordinate position moves are consistent with each other before and after the calibration fixture moves in the first direction and the second direction; and identifying a first translation vector for translating the first coordinate system and a second translation vector for translating the second coordinate system, so that the distance between the first element to be measured and the second element to be measured is equal before and after the calibration fixture is rotated.

[0020] The calibration method may also include: after identifying the first rotation matrix, the second rotation matrix, the first translation vector and the second translation vector, transforming the first coordinate position and the second coordinate position into a calibration coordinate system by (i) rotating the first coordinate position using the first rotation matrix and translating the rotated first coordinate position using the first translation vector and (ii) rotating the second coordinate position using the second rotation matrix and translating the rotated second coordinate position using the second translation vector.

[0021] A third aspect of the present disclosure provides a measurement system, comprising: a measurement device for measuring a three-dimensional geometric shape of a measurement object; and a calibration fixture for calibrating the measurement device, wherein the measurement device comprises: a moving part, which is equipped with the measurement object and moves the measurement object; a light source, which is used to irradiate light onto the measurement object; a plurality of camera parts, which are used to respectively photograph a plurality of different areas of the measurement object; a measurement part, which is used to measure the three-dimensional geometric shape of the measurement object based on the photographing results of the plurality of camera parts; a control part, which is used to control the moving part, the camera part and the measurement part; and an identification part, which is used to identify calibration parameters for calibrating the measurement results of the measurement part, and the calibration fixture comprises: a plurality of to-be-measured a measuring element; and a frame portion to which the plurality of elements to be measured are attached, wherein each of the plurality of elements to be measured includes: a main body portion having a predetermined shape; and a plurality of label portions provided on the main body portion, wherein identification codes for identifying the elements to be measured are shown on the respective label portions, the control portion causes the plurality of imaging portions to photograph subsets of the plurality of elements to be measured, the subsets being different from each other, the measuring portion analyzes the label portions of the plurality of elements to be measured corresponding to the respective photographed images of the plurality of photographed images photographed by the plurality of imaging portions to identify the positional relationship between the plurality of elements to be measured, and the identifying portion identifies calibration parameters for calibrating the plurality of imaging portions according to the identified positional relationship of the plurality of elements to be measured.

[0022] Effects of the Invention

[0023] According to the present disclosure, a measuring device for measuring a three-dimensional geometric shape of a measurement object can be easily calibrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A configuration example of a measurement system S according to the present embodiment is shown.

[0025] Figure 2 An example is shown in which the calibration jig 30 is mounted on the measuring device 10 according to the present embodiment.

[0026] Figure 3A configuration example of the control unit 140 according to the present embodiment is shown.

[0027] Figure 4 An example of the operation flow of the measuring device 10 according to the present embodiment is shown.

[0028] Figure 5 (A) to (C) each show a first example of the coordinate position of the component to be measured 31 recognized by the measuring section 243 according to the present embodiment.

[0029] Figure 6 (A) to (C) each show a second example of the coordinate position of the component to be measured 31 recognized by the measuring section 243 according to the present embodiment.

[0030] Figure 7 An example of the operation flow of the control section 240 according to the present embodiment is shown.

[0031] Figure 8 A configuration example of the calibration jig 300 according to the present embodiment is shown.

[0032] Fig. 9 (A) and (B) each show a first configuration example of the element to be measured 31 according to the present embodiment.

[0033] Fig.10 Show that it can be based on Fig. 9 (A) and (B) show examples of brightness signals obtained by the label section 33.

[0034] Fig.11 (A) to (C) show examples of steps involved in image processing performed by the control section 240 on the image pickup result of the image pickup section 132 according to the present embodiment.

[0035] Fig.12 (A) and (B) each show a second configuration example of the element to be measured 31 according to the present embodiment.

[0036] Fig.13 Show that it can be based on Fig.12 (A) and (B) show examples of brightness signals obtained by the label section 33.

[0037] Fig.14 (A) and (B) each show a third configuration example of the element to be measured 31 according to the present embodiment.

[0038] Fig.15 A fourth configuration example of the element to be measured 31 according to the present embodiment is shown.

[0039] Fig.16 A second configuration example of the calibration jig 300 according to the present embodiment is shown.

[0040] [Explanation of Reference Numerals]

[0041] 10. Measuring equipment

[0042] 30 Calibration fixture

[0043] 31 Components to be measured

[0044] 32 Main body

[0045] 33 Label Department

[0046] 34 Plate components

[0047] 35 Identification code

[0048] 36 Identification code

[0049] 40 Frame

[0050] 110 Stage

[0051] 120 Mobile Department

[0052] 130 Optical unit

[0053] 131 Light Source

[0054] 132 Camera Department

[0055] 133 Field of view

[0056] 140 Control Unit

[0057] 210 Ministry of Communications

[0058] 220 Storage

[0059] 230 Display unit

[0060] 240 Control Department

[0061] 241 Signal output unit

[0062] 242 Acquisition Department

[0063] 243 Measurement Department

[0064] 244 Rotation Matrix Identification Unit

[0065] 245 Translation vector recognition unit

[0066] 300 Calibration Fixture DETAILED DESCRIPTION

[0067] <Configuration example of measurement system S>

[0068] Figure 1A configuration example of a measuring system S according to the present embodiment is shown. The measuring system S includes a measuring device 10 and a calibration jig 30 .

[0069] The measuring device 10 measures the three-dimensional geometric shape of the measuring object W (hereinafter referred to as the workpiece W) arranged in a three-dimensional space by irradiating light from multiple directions to the measuring object W (hereinafter referred to as the workpiece W) and receiving reflected light. In addition, the measuring device 10 irradiates light from multiple directions to the calibration fixture 30 arranged in the three-dimensional space, and recognizes calibration parameters for calibration of the measuring device 10 itself by receiving reflected light. The measuring device 10 includes a stage 110, a moving part 120, an optical unit 130, and a control unit 140.

[0070] The stage 110 is provided with a measuring object W. When the measuring system S calibrates the measuring device 10, the stage 110 is provided with a calibration fixture 30. The stage 110 is configured to be movable in a plurality of predetermined directions. In the present embodiment, an example in which the stage 110 is configured to be movable in a first direction and in a second direction different from the first direction will be described. For example, the first direction and the second direction are orthogonal.

[0071] For example, the stage 110 has a function of an XY stage that can move in the X direction and the Y direction in the XY plane. In this case, the first direction is the X direction or the Y direction, and the second direction is the Y direction or the X direction.

[0072] The stage 110 is configured to be rotatable around an axis oriented in a plurality of predetermined directions. In the present embodiment, an example in which the stage 110 is configured to be rotatable around an axis oriented in a third direction and a fourth direction different from the third direction, respectively, will be described. For example, the third direction and the fourth direction are orthogonal. Here, the first direction and the third direction may coincide with each other, or the second direction and the fourth direction may coincide with each other.

[0073] For example, the stage 110 has the function of a rotating stage that can rotate around an axis oriented in the X direction and the function of a rotating stage that can rotate around an axis oriented in the Y direction. In this case, the third direction is the X direction or the Y direction, and the fourth direction is the Y direction or the X direction. The measuring device 10 needs to be configured so that the calibration fixture 30 can be moved, and a movable arm or the like that can be moved while fixing the calibration fixture 30 may be provided instead of the stage 110.

[0074] The moving part 120 moves the stage 110. In other words, when the measuring object W is mounted on the stage 110, the moving part 120 moves the measuring object W. When the calibration fixture 30 is mounted on the stage 110, the moving part 120 moves the calibration fixture 30. The moving part 120 includes an actuator such as a motor, etc., and moves the stage 110 in the first direction or the second direction. In addition, the moving part 120 rotates the stage 110 around an axis oriented in a third direction. Similarly, the moving part 120 rotates the stage 110 around an axis oriented in a fourth direction.

[0075] The optical unit 130 includes a light source 131 and an imaging unit 132. The light source 131 irradiates light onto the measuring object W. The light source 131 includes at least one of a halogen lamp, an LED, a laser beam, and the like. For example, the light source 131 is a projector for irradiating light of a predetermined pattern. The light emitted from the light source 131 is reflected by the measuring object W. When the reflected light from the measuring object W is incident on the imaging unit 132, the imaging unit 132 photographs the measuring object W. The imaging unit 132 includes a camera capable of photographing still images, videos, and the like. The imaging unit 132 may include a plurality of cameras.

[0076] A plurality of optical units 130 are arranged at different positions of the measuring device 10. In other words, a plurality of light sources 131 irradiate light onto different regions of the measuring object W, and a plurality of imaging units 132 respectively photograph a plurality of different regions of the measuring object W. For example, the imaging units 132 of the plurality of optical units 130 respectively photograph different parts of the measuring object W. In this case, it is desirable that the plurality of optical units 130 are arranged so that the overall configuration of the measuring object W can be grasped by synthesizing a plurality of photographing results obtained by the plurality of imaging units 132. For simplicity, an example in which two optical units 130 are arranged is described in the present embodiment, but the present disclosure is not limited thereto. Three or more optical units 130 may be arranged.

[0077] The control unit 140 controls the moving part 120 and the optical unit 130. When the measuring object W is mounted on the stage 110, the control unit 140 acquires the photographing result of the measuring object W photographed by the photographing part 132 from the optical unit 130, and measures the three-dimensional geometric shape of the measuring object W based on the acquired photographing result. When the calibration jig 30 is mounted on the stage 110, the control unit 140 acquires the photographing result of the calibration jig 30 photographed by the photographing part 132 from the optical unit 130, and identifies the calibration parameters to be used for calibration of the measuring device 10 based on the acquired photographing result. The control unit 140 will be described later.

[0078] The calibration jig 30 includes a plurality of elements to be measured 31 having a predetermined shape, and is a jig for calibrating the measuring device 10. In the present embodiment, an example is described in which the calibration jig 30 includes the elements to be measured 31 thereon. When the calibration jig 30 is mounted on the stage 110, it is desirable to arrange the plurality of elements to be measured 31 so that the plurality of elements to be measured 31 are included in the field of view of the imaging section 132 included in one optical unit 130.

[0079] Figure 2 An example is shown in which the calibration jig 30 is mounted on the measuring device 10 according to the present embodiment.

[0080] Figure 2 An example is shown in which the first element to be measured 31 a is in the field of view 133 a of the first imaging portion 132 a of the first optical unit 130 a and the second element to be measured 31 b is in the field of view 133 b of the second imaging portion 132 b of the second optical unit 130 b.

[0081] In the present embodiment, an example is shown in which different elements to be measured 31 are included in the field of view 133a of the first imaging unit 132a and the field of view 133b of the second imaging unit 132b, but the present embodiment is not limited thereto. For example, part or all of the first element to be measured 31a may be in the field of view 133a of the first imaging unit 132a, and part or all of the first element to be measured 31a may be in the field of view 133b of the second imaging unit 132b.

[0082] Each optical unit 130 can photograph the element to be measured 31 in the field of view of the optical unit 130 by irradiating light from the light source 131 onto the calibration fixture 30 and photographing the image using the camera unit 132. Then, the control unit 140 obtains the photographing result from the camera unit 132 and measures the three-dimensional geometric shape of the element to be measured 31. The element to be measured 31 has a predetermined size and a predetermined shape. The element to be measured 31 can be formed to have a predetermined size. The element to be measured 31 can have different shapes, marks, colors, etc. In the present embodiment, an example in which the element to be measured 31 is spherical and the control unit 140 measures the center position of the sphere will be described.

[0083] Here, the sizes and positional relationships of the plurality of components to be measured 31 set in the calibration fixture 30 may be known in advance. In this case, the control unit 140 may calibrate the measuring device 10 by comparing (i) the known sizes and positional relationships of the components to be measured 31 and (ii) the measurement results of the three-dimensional geometric shapes of the components to be measured 31. For example, the control unit 140 identifies a coefficient or the like to be multiplied by the measurement results of the three-dimensional geometric shapes as calibration parameters, so that the measurement results of the three-dimensional geometric shapes of the components to be measured 31 match the sizes and positional relationships of the components to be measured 31.

[0084] However, in the case of the measuring device 10 for measuring a large measuring object, the calibration fixture 30 also becomes large, and it is sometimes difficult to measure the precise size. In addition, in the case of the measuring device 10 for measuring a complex measuring object, the shape and arrangement of the calibration fixture 30 become complicated, and it is sometimes difficult to measure the precise size.

[0085] On the other hand, even if the dimensions of such a calibration jig 30 can be measured, the dimensions may vary due to environmental changes, etc., or shocks may cause dimensional deviations, etc., so it is difficult to easily calibrate the measuring device 10. Therefore, the measuring system S according to the present embodiment makes it possible to calibrate such a measuring device 10 even with a calibration jig 30 having a plurality of elements to be measured 31 whose dimensions and positional relationships are unknown. The control unit 140 of the measuring device 10 will now be described.

[0086] <Configuration Example of Control Unit 140>

[0087] Figure 3 The configuration example of the control unit 140 according to the present embodiment is shown. The control unit 140 is, for example, a computer. The control unit 140 includes a communication section 210 , a storage section 220 , a display section 230 , and a control section 240 .

[0088] The communication unit 210 communicates with the moving unit 120 and the optical unit 130. For example, the communication unit 210 sends a control signal for moving the measuring object W or the calibration jig 30 to the moving unit 120. The communication unit 210 may send a control signal for controlling the light source 131 and the imaging unit 132 to the optical unit 130. The communication unit 210 may receive the photographing result of the imaging unit 132 from the optical unit 130.

[0089] The communication section 210 performs communication via a dedicated connection line and a communication network, etc. The communication section 210 can be used as an interface for connecting to a communication network such as an Internet line, a wireless LAN, or a mobile phone network.

[0090] The storage unit 220 includes a storage medium such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The storage unit 220 may include a large-capacity storage device such as a hard disk drive (HDD) and / or a solid-state drive (SSD). For example, when a computer is used as the control unit 140, the storage unit 220 may store an OS (Operating System) that enables the computer to function and information such as programs. The storage unit 220 may store various types of information including data to be referenced when executing a program.

[0091] The storage unit 220 may store intermediate data, calculation results, thresholds, reference values, parameters, etc. generated (or used) in the operation process of the control unit 140. In addition, in response to a request from each part of the control unit 140, the storage unit 220 may provide the stored data to the request source.

[0092] The display unit 230 displays information related to the measurement of the measuring device 10. The display unit 230 displays information such as measurement conditions, measurement items, and measurement results. The display unit 230 can display the communication status of the control unit 140, the execution status of the OS and the application, etc. The display unit 230 is, for example, a display such as a liquid crystal display or a monitor.

[0093] The control unit 240 controls each unit of the measuring device 10. For example, the control unit 240 sends and receives various types of information via the communication unit 210. The control unit 240 is, for example, a CPU (central processing unit). The control unit 240 controls the moving unit 120 and the imaging unit 132 to measure the three-dimensional geometric shape of the measuring object W based on the photographing results of the plurality of imaging units 132.

[0094] The control section 240 includes a signal output section 241, an acquisition section 242, a measurement section 243, a rotation matrix identification section 244, and a translation vector identification section 245. In other words, by executing the program stored in the storage section 220, the CPU functions as the control section 240 including the signal output section 241, the acquisition section 242, the measurement section 243, the rotation matrix identification section 244, and the translation vector identification section 245.

[0095] The signal output section 241 outputs a control signal for controlling each section of the measuring device 10 to the communication section 210. For example, the signal output section 241 outputs a control signal for controlling the light source 131 and the imaging section 132 of the optical unit 130. As an example, the signal output section 241 outputs a control signal for causing the light source 131 of one optical unit 130 to emit light in a predetermined pattern and a control signal for causing the imaging section 132 of one optical unit 130 to capture an image. By doing so, the communication section 210 transmits the control signal to the one optical unit 130, and the one optical unit 130 captures an image of the object (e.g., the element to be measured 31) in its field of view.

[0096] The signal output unit 241 outputs a control signal for driving the moving unit 120. The signal output unit 241 may output a control signal for causing the display unit 230 to display information, etc. The signal output unit 241 may generate a control signal corresponding to an operation purpose, or may output a control signal having a predetermined signal pattern. The signal pattern of the control signal may be stored in the storage unit 220.

[0097] The acquisition unit 242 acquires data of an image captured by the imaging unit 132 of the optical unit 130 as a capture result. The acquisition unit 242 may store the acquired capture result of the imaging unit 132 in the storage unit 220. The acquisition unit 242 may also acquire information on the current position of the stage 110.

[0098] The measuring unit 243 measures the three-dimensional geometric shape of the measuring object W or the calibration fixture 30 based on the photographing results of the imaging unit 132 acquired by the acquiring unit 242. For example, the measuring unit 243 measures the length of a predetermined portion of the measuring object W and the size of a predetermined shape. By using the photographing results of multiple imaging units 132, the measuring unit 243 can also measure the length and shape of a predetermined portion of the measuring object W that cannot be accommodated in the field of view of one imaging unit 132. Since the operation of the measuring unit 243 to measure the three-dimensional geometric shape of the measuring object W based on the photographing results of multiple imaging units 132 is well known, its detailed description is omitted here.

[0099] The rotation matrix identification section 244 identifies a rotation matrix used for calibration of the measuring device 10. The translation vector identification section 245 identifies a translation vector used for calibration of the measuring device 10. The operations of the rotation matrix identification section 244 and the translation vector identification section 245 will be described below.

[0100] <Example of Operation Flow of Measuring Device 10>

[0101] Figure 4 An example of the operation flow of the measuring device 10 according to the present embodiment is shown. The measuring device 10 performs Figure 4 The operations from S51 to S66 are shown to identify calibration parameters for calibration of the measuring device 10 itself. Although the measuring device 10 includes a plurality of optical units 130, in this operation flow, an operation example using the first optical unit 130a and the second optical unit 130b will be described in a simplified manner.

[0102] First, before calibrating the measuring device 10 using the calibration jig 30, the measuring device 10 calibrates each optical unit 130. In this case, the measuring device 10 calibrates each optical unit 130 using a reference jig smaller in size than the calibration jig 30. For example, the size of the reference jig is the size of the field of view of the imaging unit 132 included in one optical unit 130.

[0103] The reference fixture has a plurality of reference measurement elements of which at least one of size and positional relationship is known. As an example, the reference measurement element has a shape approximately the same as the element to be measured 31. Alternatively, the reference fixture may have a shape of known size. Such a small reference fixture has hardly changed over time and is a commonly used fixture that is easy to handle. Since it is well known to calibrate each optical unit 130 using such a reference fixture, the operation of calibration will be briefly described here.

[0104] First, a reference fixture is mounted on the stage 110 of the measuring device 10 (S51). A plurality of reference fixtures may be mounted on the stage 110, or alternatively, one reference fixture may be mounted on the stage 110. In the case where a plurality of reference fixtures are mounted on the stage 110, it is desirable to arrange the plurality of reference fixtures so that they are included in the respective fields of view of the optical unit 130. Then, the control unit 240 calibrates the respective optical units 130 (S52).

[0105] For example, the control unit 240 photographs the reference fixture using the first imaging unit 132a of the first optical unit 130a, and calibrates the first coordinate system for indicating the first coordinate position in the field of view 133a of the first imaging unit 132a based on the photographing result of the first imaging unit 132a. Then, the control unit 240 identifies the first coefficient to be multiplied by the measurement result of the three-dimensional geometric shape so that the measurement result of the three-dimensional geometric shape of the reference measurement element of the reference fixture matches the size and positional relationship of the known reference measurement element.

[0106] Next, the control unit 240 uses the second camera 132b of the second optical unit 130b to photograph the reference jig, and calibrates the second coordinate system for indicating the second coordinate position in the field of view 133b of the second camera 132b based on the photographing result of the second camera 132b. In the case where one reference jig is mounted on the stage 110, for example, when the calibration of the first optical unit 130a is completed, the control unit 240 moves the stage 110 so that the reference jig is included in the field of view of the second optical unit 130b to be calibrated next, and then starts the calibration of the second optical unit 130b.

[0107] In a manner similar to the calibration of the first optical unit 130a, the control unit 240 identifies a second coefficient to be multiplied by the measurement result of the three-dimensional geometric shape so that the measurement result of the three-dimensional geometric shape of the reference measurement element based on the photographing result of the second camera 132b matches the size and positional relationship of the known reference measurement element. As described above, the control unit 240 calibrates each of the plurality of optical units 130. The control unit 240 may store the identified coefficient in the storage unit 220.

[0108] Next, a calibration fixture 30 is mounted on the stage 110 of the measuring device 10 (S53). Next, the control unit 240 photographs the calibration fixture 30 arranged at the first reference position (S54). For example, the first reference position is a predetermined position such as the initial position of the stage 110. For example, when the calibration fixture 30 is arranged at the first reference position, it is desirable to predetermine the positional relationship between the calibration fixture 30, the plurality of optical units 130, and the first reference position so that the plurality of elements to be measured 31 of the calibration fixture 30 are in the field of view 133 of the plurality of imaging units 132.

[0109] For example, the control section 240 moves the stage 110 and then arranges the calibration jig 30 at the first reference position. Then, after turning on the light sources 131 of the plurality of optical units 130, the control section 240 photographs the calibration jig 30 by using the imaging section 132. By doing so, at the first reference position, the first imaging section 132a photographs the first element to be measured 31a among the plurality of elements to be measured 31 included in the calibration jig 30, and the second imaging section 132b different from the first imaging section 132a photographs the second element to be measured 31b different from the first element to be measured 31a.

[0110] Next, the control unit 240 moves the calibration fixture 30 from the first reference position in a predetermined first direction (S55). For example, the control unit 240 moves the stage 110 by a predetermined distance in the first direction. It is desirable that the control unit 240 moves the stage 110 in the first direction within a range where the plurality of elements to be measured 31 of the calibration fixture 30 are included in the field of view of the plurality of imaging units 132.

[0111] Then, the control part 240 photographs the calibration jig 30 by using the plurality of optical units 130 (S56). After turning on the light sources 131 of the plurality of optical units 130, the control part 240 photographs the calibration jig 30 by using the imaging part 132. By doing so, the first imaging part 132a photographs the first component to be measured 31a that has moved in the first direction, and the second imaging part 132b photographs the second component to be measured 31b that has moved in the first direction.

[0112] Next, the control unit 240 moves the calibration jig 30 from the first reference position in a predetermined second direction different from the first direction (S57). For example, after the stage 110 is moved back to the first reference position, the control unit 240 moves the stage 110 in the second direction by a predetermined distance. Alternatively, after moving the stage 110 in the second direction by a predetermined distance, the control unit 240 may move the stage 110 back in the direction opposite to the first direction by the distance moved in S55.

[0113] Alternatively, the control unit 240 may move the stage 110 in the second direction by a predetermined distance and subtract the distance moved in S55 from the measurement result. It is desirable that the control unit 240 moves the stage 110 in the second direction within a range where the plurality of elements to be measured 31 of the calibration jig 30 are included in the field of view of the plurality of imaging units 132.

[0114] Then, the control section 240 photographs the calibration jig 30 by using the plurality of optical units 130 (S58). The control section 240 photographs the calibration jig 30 through the same operation as in S56. By doing so, the first imaging section 132a photographs the first component to be measured 31a that has moved in the second direction, and the second imaging section 132b photographs the second component to be measured 31b that has moved in the second direction.

[0115] Next, the control unit 240 photographs the calibration fixture 30 arranged at the second reference position (S59). The second reference position is, for example, a predetermined position such as the initial position of the stage 110. Similar to the first reference position, the second reference position is a position where the plurality of elements to be measured 31 of the calibration fixture 30 are in the field of view 133 of the plurality of imaging units 132 when the calibration fixture 30 is arranged at the second reference position.

[0116] For example, after moving the stage 110 to the second reference position, the control section 240 photographs the calibration jig 30 by using the camera section 132 in the same manner as the operation in S54. The second reference position may be a position after the calibration jig 30 has been moved in the second direction. In this case, since the operation in S59 has the same result as the operation in S58, the operation in S59 may be omitted. In addition, the second reference position may be the same position as the first reference position, and in this case, since the operation in S59 has the same result as the operation in S54, the control section 240 may simply move the calibration jig 30 to the second reference position.

[0117] Next, the control unit 240 rotates the calibration jig 30 in a predetermined direction around an axis oriented in a predetermined third direction (S60). For example, the control unit 240 rotates the stage 110 by a predetermined angle θ within a range where the plurality of components to be measured 31 of the calibration jig 30 are within the field of view 133 of the plurality of imaging units 132.

[0118] Then, the control section 240 photographs the calibration jig 30 (S61) by using the plurality of optical units 130. The control section 240 photographs the calibration jig 30 by performing the same operation as in S56. As a result, the first imaging section 132a photographs the first component to be measured 31a after being rotated around the axis oriented in the third direction, and the second imaging section 132b photographs the second component to be measured 31b after being rotated around the axis oriented in the third direction.

[0119] Next, the control unit 240 rotates the calibration fixture 30 in a predetermined direction around an axis oriented in a predetermined fourth direction (S62), wherein the predetermined fourth direction is different from the third direction. For example, after rotating the stage 110 back to a predetermined angle θ around the axis oriented in the third direction, the control unit 240 rotates the stage 110 around the axis oriented in the fourth direction by a predetermined angle within a range where the plurality of components to be measured 31 of the calibration fixture 30 are within the field of view 133 of the plurality of imaging units 132.

[0120] Alternatively, after rotating the stage 110 by a predetermined angle around an axis oriented in the fourth direction Afterwards, the control section 240 may rotate the stage 110 back to the predetermined angle θ around the axis oriented in the third direction. Alternatively, the control section 240 may rotate the stage 110 around the axis oriented in the fourth direction by a predetermined angle θ. and subtracting from the measurement result the predetermined angle at which the stage 110 is rotated about an axis oriented in the fourth direction. The amount of rotation.

[0121] The control section 240 photographs the calibration jig 30 using the plurality of optical units 130 (S63). The control section 240 photographs the calibration jig 30 by the same operation as in S61. As described above, the control section 240 outputs a control signal from the signal output section 241, and while moving the calibration jig 30, photographs the component to be measured 31 with the plurality of imaging sections 132 before and after the movement of the calibration jig 30. Then, the acquisition section 242 acquires the photographing result of the imaging section 132.

[0122] exist Figure 4 , an example is described in which the control unit 240 sequentially performs the following operations: moving the calibration jig 30 in a first direction, moving the calibration jig 30 in a second direction, rotating the calibration jig 30 by an angle θ, and rotating the calibration jig 30 by an angle θ. However, the present disclosure is not limited thereto. The control unit 240 may be configured to Figure 4 The calibration fixture 30 is moved in a first direction, the calibration fixture 30 is moved in a second direction, the calibration fixture 30 is rotated by an angle θ, and the calibration fixture 30 is rotated by an angle θ.

[0123] Next, the control unit 240 identifies the coordinate position of the component to be measured 31 for each position to which the calibration jig 30 is moved based on the photographing results of the plurality of imaging units 132 (S64). For example, the measuring unit 243 identifies the first coordinate position indicating the position of the first component to be measured 31a in the first coordinate system based on the field of view of the first imaging unit 132a among the plurality of photographed images photographed by the first imaging unit 132a. In addition, the measuring unit 243 identifies the second coordinate position indicating the position of the second component to be measured 31b in the second coordinate system based on the field of view of the second imaging unit 132b among the plurality of photographed images photographed by the second imaging unit 132b.

[0124] <First Example of Coordinate Position of Component 31 to be Measured>

[0125] Figure 5 (A) to (C) each show a first example of the coordinate position of the component to be measured 31 recognized by the measuring section 243 according to the present embodiment. Figure 5 (A) to (C) each show that the measuring unit 243 is based on Figure 4 The results of the operation from S53 to S58 are shown to measure the center positions of three spherical elements to be measured 31 and plot the coordinate positions of the measurement results. The desired measuring section 243 calculates the coordinate positions of the measurement results using the first and second coefficients identified in the calibration operation from S51 to S52.

[0126] Figure 5 (A) shows a first coordinate system based on the photographing result of the first camera unit 132a. For example, the first coordinate position represented by a circle indicates the coordinate position of the first element to be measured 31a at the first reference position. The first coordinate position represented by a square indicates the coordinate position of the first element to be measured 31a that has moved in the first direction from the first reference position, and the first coordinate position represented by a triangle indicates the coordinate position of the first element to be measured 31a that has moved in the second direction from the first reference position. Figure 5 In the first coordinate system shown in (A), the first direction is Tx1 and the second direction is Ty1.

[0127] Figure 5 (B) shows a second coordinate system based on the photographing result of the second camera unit 132b. For example, the second coordinate position represented by a circle indicates the coordinate position of the second element to be measured 31b at the first reference position. The second coordinate position represented by a square indicates the coordinate position of the second element to be measured 31b that has moved in the first direction from the first reference position, and the second coordinate position represented by a triangle indicates the coordinate position of the second element to be measured 31b that has moved in the second direction from the first reference position. Figure 5In the second coordinate system shown in (B), the first direction is Tx2 and the second direction is Ty2.

[0128] If each of the optical units 130 has been calibrated through the operations from S51 to S52 and the like, then Figure 5 The measurement results of the coordinate positions of the same coordinates as shown in (A) to (C) etc. can be measured with the accuracy of the device performance. For example, Figure 5 The distance between the two different first elements to be measured 31a in (A) is approximately consistent with the actual distance between the first elements to be measured 31a. Similarly, Figure 5 The distance between two different second elements to be measured 31 b in (B) is also approximately consistent with the actual distance between the second elements to be measured 31 b.

[0129] However, since calibration between multiple different optical units 130 (which may be referred to as group calibration) has not been performed, the distance between certain coordinate positions of different coordinates cannot be measured with the accuracy of device performance. Figure 5 The coordinate position of a first element to be measured 31a in the first coordinate system shown in (A) and Figure 5 The distance between the coordinate positions of one second element to be measured 31 b in the second coordinate system shown in (B) does not need to be consistent with the distance between the actual first element to be measured 31 a and the actual second element to be measured 31 b .

[0130] Therefore, in order to perform group calibration, the control unit 240 first identifies the coordinate transformation to make Figure 5 The first direction Tx1 in (A) is Figure 5 The first direction Tx2 in (B) is approximately consistent, and Figure 5 The second direction Ty1 in (A) is Figure 5 The second direction Ty2 in (B) is approximately consistent with the matrix.

[0131] By recognizing such a rotation matrix, the control section 240 can calibrate the movement direction when the calibration jig 30 (the measuring object M) moves between a plurality of different optical units 130 .

[0132] In other words, Figure 4 After the operation in S64, the rotation matrix identification unit 244 of the control unit 240 identifies a rotation matrix for rotating the coordinates so that the direction in which the first coordinate position moves and the direction in which the second coordinate position moves are consistent with each other before and after the calibration fixture 30 moves in the first direction and the second direction (S65). The rotation matrix includes a first rotation matrix that rotates the first coordinate system to perform coordinate transformation and a second rotation matrix that rotates the second coordinate system to perform coordinate transformation. The details of the operation in S65 will be described later.

[0133] <Second Example of Coordinate Position of Component 31 to be Measured>

[0134] Next, the control unit 240 calibrates the translation directions between the plurality of different optical units 130 . Figure 6 (A) to (C) each show a second example of the coordinate position of the component to be measured 31 recognized by the measuring section 243 according to the present embodiment. Figure 6 (A) to (C) each show that the measuring unit 243 is based on Figure 4 An example of measuring the center position of a spherical component to be measured 31 and plotting the coordinate position of the measurement result as a result of the operation from S59 to S63.

[0135] The desired measuring section 243 calculates the coordinate position of the measurement result using the first coefficient and the second coefficient identified in the calibration operation from S51 to S52. In addition, when the rotation matrix identifying section 244 identifies the rotation matrix in S65, the desired measuring section 243 coordinate-transforms the coordinate position of the measurement result by using the identified rotation matrix.

[0136] Figure 6 (A) shows a first coordinate system based on the photographing result of the first imaging unit 132a. For example, the first coordinate position represented by a circle indicates the reference position P of the i-th first element to be measured 31a at the second reference position. i The first coordinate position represented by a square indicates a first rotation position P of the i-th first element to be measured 31a rotated from the first reference position by an angle θ about an axis oriented in the third direction. θi , and the first coordinate position represented by the triangle indicates a rotation angle from the first reference position about an axis oriented in the fourth direction The second rotation position of the i-th first element to be measured 31a

[0137] Figure 6 (B) shows a second coordinate system based on the photographing result of the second imaging unit 132b. For example, the second coordinate position represented by a circle indicates the reference position P of the j-th second element to be measured 31b at the second reference position. j The second coordinate position indicated by a square indicates a first rotation position P of the j-th second element to be measured 31 b rotated from the second reference position by an angle θ about an axis oriented in the third direction. θj , and the second coordinate position represented by the triangle indicates a rotation angle from the second reference position about an axis oriented in the fourth direction The second rotation position of the j-th second element to be measured 31b

[0138] Here, the distance between the first element to be measured 31a and the second element to be measured 31b does not change before and after the rotation of the calibration jig 30. However, if group calibration is not performed, the measurement result of the distance between the first element to be measured 31a and the second element to be measured 31b may change before and after the rotation due to exceeding the allowable value of the measurement error.

[0139] Therefore, in Figure 6 In the examples (A) to (C) of FIG. 1 , the translation vector recognition unit 245 recognizes, for example, the following translation vector, which is used to perform coordinate transformation so that the reference position P i To the reference position P j The distance from the first rotation position P θi To the first rotation position P θj The distance from the second rotation position To the second rotation position The distances of φ and φ are approximately consistent with each other. By identifying such a translation vector, the control section 240 can calibrate the distance measurement of the calibration jig 30 (measurement object M) between a plurality of different optical units 130 .

[0140] In other words, Figure 4 In the embodiment of the present invention, after the operation of S65, the translation vector identification unit 245 identifies the translation vector for translating the coordinates so that the distance between the first element to be measured 31a and the second element to be measured 31b is the same before and after the rotation (S66). The translation vector includes a first translation vector for translating the first coordinate system and a second translation vector for translating the second coordinate system. The details of the operation in S66 will be described later. The control unit 240 can store the identified rotation matrix and translation vector in the storage unit 220 as calibration parameters.

[0141] As described above, the identified rotation matrix can calibrate the moving direction of the calibration jig 30 (measuring object M), and the identified translation vector can calibrate the distance measurement of the calibration jig 30 (measuring object M) between the plurality of different optical units 130. Therefore, the control section 240 can perform group calibration by using the rotation matrix and translation vector identified by the above operation.

[0142] For example, when executing Figure 4After the operation flow shown, the measuring device 10 mounts the measuring object M on the stage 110, and uses the first optical unit 130a and the second optical unit 130b to measure the three-dimensional geometric shape of the measuring object M. Then, the measuring part 243 transforms the coordinates of the first coordinate system into the calibration coordinate system by rotating the coordinate position of the first coordinate system using the first rotation matrix and translating the rotated position using the first translation vector. In addition, the measuring part 243 transforms the coordinates of the second coordinate system into the calibration coordinate system by rotating the coordinate position of the second coordinate system using the second rotation matrix and translating the rotated coordinate position using the second translation vector.

[0143] By doing so, the control unit 240 can output the measurement value of the three-dimensional geometric shape in the calibration coordinate system as the calibrated measurement value. The control unit 240 can cause the display unit 230 to display the calibrated measurement value or store the calibrated measurement value in the storage unit 220. In addition, the control unit 240 can output the calibrated measurement value to an external device via a network or the like.

[0144] As described above, in the measuring system S according to the present embodiment, even when the calibration jig 30 whose sizes and positional relationships of the plurality of components 31 to be measured are unknown is used, it is possible to identify the calibration parameters to be used for calibration of the measuring system S itself and reflect the calibration parameters in the measurement results. Therefore, based on the measuring system S according to the present embodiment, the measuring device 10 for measuring the three-dimensional geometry of a large measuring object W can be easily calibrated.

[0145] <Example of Operation Flow of Control Unit 240>

[0146] Figure 7 An example of the operation flow of the control section 240 according to the present embodiment is shown. Figure 7 Shown for illustration Figure 4 An example of the operation flow of the measurement device 10 is shown with details of the operations in S65 and S66. Figure 7 The operations in S71 to S73 are the same as Figure 4 The detailed operations correspond to those in S65.

[0147] First, the rotation matrix identification unit 244 generates a first centroid matrix x (S71) based on the matrix X1 for indicating the first coordinate position, the matrix X2 for indicating the first coordinate position after the calibration fixture 30 moves in the first direction, and the matrix X3 for indicating the first coordinate position after the calibration fixture 30 moves in the second direction.

[0148] The rotation matrix identification unit 244 converts the matrix x used to indicate the first coordinate position of the i-th first element to be measured 31a into 1i Defined as the elements of the matrix X1. For example, the element x1i is a matrix of three rows and one column for indicating a point in Cartesian coordinates. In other words, the rotation matrix identification section 244 defines a matrix indicating N first coordinate positions as a result of measuring the positions of N first elements to be measured 31a by the first optical unit 130a as a matrix X1=[x 11 ,…,x 1N ].

[0149] In addition, the rotation matrix identification unit 244 converts the matrix x indicating the first coordinate position of the i-th first element to be measured 31a after the calibration jig 30 moves in the first direction into 2i Defined as the element x of the matrix X2 2i , and define the matrix X2 as [x 21 ,…,x 2N ]. Similarly, the matrix x for indicating the first coordinate position of the i-th first component to be measured 31a after the calibration fixture 30 moves in the second direction is 3i Defined as the element x of the matrix X3 3i , and define the matrix X3 as [x 31 ,…,x 3N ].

[0150] Then, the rotation matrix identification unit 244 calculates the centroids of the generated matrices X1, X2, and X3, respectively, and generates a first centroid matrix x=[x1, x2, x3], which is a matrix having the calculated three centroids x1, x2, and x3 as its elements. k It is calculated by the following formula, where (k=1, 2, 3).

[0151] [Formula 1]

[0152]

[0153] Next, the rotation matrix identification unit 244 generates a second centroid matrix y (S72) based on the matrix Y1 for indicating the second coordinate position, the matrix Y2 for indicating the second coordinate position after the calibration fixture 30 moves in the first direction, and the matrix Y3 for indicating the second coordinate position after the calibration fixture 30 moves in the second direction.

[0154] Similar to the case of generating the first centroid matrix x, the rotation matrix identification unit 244 defines a matrix for indicating the second coordinate position of the i-th second element to be measured 31 b as the element y 1i Then, the rotation matrix identification section 244 defines the matrix Y1 as (the number M of the second elements to be measured 31b is defined as the number of elements) [y 11 ,…,y1M ], the element y 2i The matrix Y2, which is a matrix for indicating the second coordinate position of the calibration jig 30 after it moves in the first direction, is defined as [y 21 ,…,y 2M ], and the element y 3i The matrix Y3, which is a matrix for indicating the second coordinate position of the calibration jig 30 after it moves in the second direction, is defined as [y 31 ,…,y 3M ].

[0155] The rotation matrix identification unit 244 calculates the centroids of the generated matrices Y1, Y2, and Y3, respectively, and generates a matrix having the calculated three centroids y1, y2, and y3 as elements as a second centroid matrix y=[y1, y2, y3]. k It is calculated by the following formula, where (k=1, 2, 3).

[0156] [Formula 2]

[0157]

[0158] Next, the rotation matrix identification unit 244 identifies the first rotation matrix and the second rotation matrix by aligning the coordinate positions indicated by the elements of the first centroid matrix x and the coordinate positions indicated by the elements of the second centroid matrix y in pairs (S73). Here, although the pairwise alignment is a known technology as described in non-patent document 1, the details are described below.

[0159] <An example of pairwise alignment>

[0160] For example, pairwise alignment of two data matrices is a technique that computes a rotation matrix R and a translation vector t that relate corresponding points (elements) as shown below.

[0161] [Formula 3]

[0162]

[0163] First, the rotation matrix R and the translation vector t are initialized. In addition, the evaluation function C used to represent the average position offset of the coordinate position is set. PRE The initial value of (for example 0).

[0164] [Formula 4]

[0165]

[0166] t=[1 1 1] T

[0167] C pre =0

[0168] Next, the evaluation function C for representing the average position shift amount of the coordinate position is calculated as follows: It should be noted that when this example is applied to the following equation, L=3.

[0169] [Formula 5]

[0170]

[0171] Next, the centroid of each of the two data matrices is calculated as follows.

[0172] [Formula 6]

[0173]

[0174] Next, the two data matrices are converted into a matrix W of a barycenter-centered coordinate system, and the matrix W is subjected to singular value decomposition as shown in the following equation.

[0175] [Formula 7]

[0176]

[0177] By using the matrix U and the matrix V obtained by singular value decomposition, the rotation matrix R can be calculated as shown below C .

[0178] [Formula 8]

[0179] R c =Vdiag(1,1,det(VU T ))U T

[0180] In addition, using the calculated rotation matrix R C , the translation vector t can be calculated as follows C .

[0181] [Formula 9]

[0182]

[0183] Using the calculated rotation matrix R C and the translation vector t C , update the data matrix, rotation matrix and translation vector as shown below.

[0184] [Formula 10]

[0185] x i ←R c x i +t c

[0186] R←R cR

[0187] t←R c t+t C

[0188] Next, calculate the change in the value of the evaluation function |C pre -C|, and compare the calculated result with the threshold d Cth For example, when |C pre -C|≥d Cth When C pre The value of is updated to the value of C, and the calculation from equation 5 to equation 10 is performed. The calculation from equation 5 to equation 10 is repeated until |C pre -C| <d Cth Until. When |C pre -C| <d Cth When |C pre -C| <d Cth , it can be determined as a pair misalignment.

[0189] The rotation matrix R and translation vector t calculated as described above are used to perform coordinate transformation on the data matrix y as shown below, so that the data matrix y can be aligned with the data matrix x.

[0190] [Formula 11]

[0191]

[0192] By applying the above pairwise alignment, the rotation matrix identification unit 244 identifies the first rotation matrix as a unit matrix, and can identify the second rotation matrix R as shown on the right side of Formula 11. For example, the measurement unit 243 applies such a rotation matrix R to Figure 5 The second coordinate shown in (B) is transformed into Figure 5 By doing so, the measuring unit 243 can convert the first direction Tx2 and the second direction Ty2 of the second coordinate system into the first direction Tx3 and the second direction Ty3 of the third coordinate system, so that the first direction Tx2 and the second direction Ty2 of the second coordinate system are consistent with each other. Figure 5 The first direction Tx1 and the second direction Ty1 of (A) are approximately consistent.

[0193] As described above, the rotation matrix identification section 244 identifies the rotation matrix R by performing pairwise alignment using the first barycenter matrix x and the second barycenter matrix y as two corresponding data matrices.

[0194] Next, the translation vector identification unit 245 Figure 4 The translation vector is identified in S66 of . In this case, Figure 7The operation from S74 to S76 is Figure 4 It should be noted that in S64, the control section 240 identifies the coordinate position of the component to be measured 31 for each position to which the calibration jig 30 is moved.

[0195] For example, based on the photographing result obtained when the calibration jig 30 is arranged at the second reference position in S59, the control section 240 generates a matrix indicating the first coordinate position, wherein the element x is defined as 1i And the number N of the first elements to be measured 31a is a matrix of the number of elements X1=[x 11 ,…,x 1N ]. In addition, the control portion 240 generates a matrix indicating the first coordinate position of the calibration jig 30 after the calibration jig 30 is rotated around the axis oriented in the third direction in S60, and the matrix is ​​defined as an element x 4i The matrix X4 = [x 41 ,…,x 4N ], and a matrix indicating the first coordinate position of the calibration jig 30 after the calibration jig 30 is rotated around the axis oriented in the fourth direction in S62 is defined as the element x 5i The matrix X5 = [x 51 ,…,x 5N ].

[0196] Similarly, based on the photographing result obtained when the calibration jig 30 is arranged at the second reference position in S59, the control section 240 generates a matrix indicating the second coordinate position, which is defined as the element y 1i And the number M of the second elements to be measured 31b is a matrix of the number of elements Y1=[y 11 ,...,y 1M ]. In addition, the control portion 240 generates a matrix indicating the second coordinate position of the calibration jig 30 after the calibration jig 30 is rotated around the axis oriented in the third direction in S60, and the element y is defined as 4i The matrix Y4=[y 41 ,...,y 4M ], and a matrix indicating the second coordinate position of the calibration jig 30 after the calibration jig 30 is rotated around the axis oriented in the fourth direction in S62 is defined as the element y 5i The matrix Y5=[y 51 ,…,y 5M ].

[0197] Then, the translation vector identification unit 245 generates a first calibration matrix, a second calibration matrix, and a third calibration matrix (S74), wherein the first calibration matrix, the second calibration matrix, and the third calibration matrix are calibrated by rotating the generated matrices X1, X4, and X5 using the first rotation matrix. Here, the i-th element of the first calibration matrix is ​​represented by P iIndicates that the i-th element of the second calibration matrix is ​​P θi , and the i-th element of the third calibration matrix is ​​represented by express. Figure 6 (A) shows the plot of P i , P θi and .

[0198] In addition, the translation vector identification unit 245 generates a fourth calibration matrix, a fifth calibration matrix, and a sixth calibration matrix, wherein the fourth calibration matrix, the fifth calibration matrix, and the sixth calibration matrix are calibrated by rotating the generated matrices Y1, Y4, and Y5 using the second rotation matrix. Here, the jth element of the fourth calibration matrix is ​​represented by p j Indicates that the jth element of the fifth calibration matrix is ​​p θj , and the jth element of the sixth calibration matrix is ​​given by express. Figure 6 (B) shows that such p is plotted j 、p θ j and .

[0199] Next, the translation vector identification unit 245 sets the distance from the coordinate position obtained by adding the first translation vector T1 to the first calibration matrix to the coordinate position obtained by adding the second translation vector T2 to the fourth calibration matrix as the first distance. The translation vector identification unit 245 sets the distance from the coordinate position obtained by adding the first translation vector T1 to the second calibration matrix to the coordinate position obtained by adding the second translation vector T2 to the fifth calibration matrix as the second distance. Similarly, the translation vector identification unit 245 sets the distance from the coordinate position obtained by adding the first translation vector T1 to the third calibration matrix to the coordinate position obtained by adding the second translation vector T2 to the sixth calibration matrix as the third distance.

[0200] Then, the translation vector identification unit 245 identifies the first translation vector T1 and the second translation vector T2 so that the first distance, the second distance and the third distance are consistent with each other. In this embodiment, an example of calculating the second translation vector T by setting the first translation vector T1 to a zero vector and setting the second translation vector T2 to T is shown.

[0201] For example, Figure 6 The translation vector T shown in (B) for performing coordinate transformation on the second coordinate system based on the imaging result of the second imaging unit 132b is used to express the coordinate position after the coordinate transformation as shown in the following equation. Figure 6 (C) shows the third coordinate system after coordinate transformation from the second coordinate system.

[0202] [Formula 12]

[0203] P j ′=p j +T

[0204] P θj ′=p θj +T

[0205]

[0206] Next, the distance from the coordinate position of the i-th first element to be measured 31a in the first coordinate system to the coordinate position of the j-th second element to be measured 31b in the third coordinate system is expressed by the following equation. Here, the first distance is d ij , the second distance is d θij , and the third distance is

[0207] [Formula 13]

[0208] d ij =|P i -P′ j |

[0209] d θij =|P θi -P θj ′|

[0210]

[0211] A function for evaluating the magnitude of the error of the distance from the coordinate position of the first element to be measured 31a of the first coordinate system to the coordinate position of the second element to be measured 31b of the third coordinate system before and after rotating the calibration jig 30 is defined as the following function S. Here, N1 is the number of the first elements to be measured 31a, and N2 is the number of the second elements to be measured 31b.

[0212] [Formula 14]

[0213]

[0214] The translation vector identification unit 245 calculates T at which the value of the function S shown in Expression 14 becomes minimum (S75). Instead of Expression 14, the translation vector identification unit 245 may calculate T at which the value of the following Expression becomes minimum.

[0215] [Formula 15]

[0216]

[0217] Since the operation of calculating T by minimizing S in Formula 14 or S in Formula 15 can be performed by a known method, a detailed description of the operation is omitted here. Then, the translation vector identification unit 245 identifies T used to minimize the value of S in Formula 14 or S in Formula 15 as the translation vector T (S76).

[0218] Thus, the rotation matrix identification unit 244 and the translation vector identification unit 245 can identify the rotation matrix R and the translation vector T as parameters for calibration of the measuring device 10. The measuring device 10 can measure the three-dimensional geometry of the measuring object W with the accuracy of the device performance by calibrating itself using the identified rotation matrix R and the translation vector T.

[0219] As described above, the measuring device 10 according to the present embodiment identifies the calibration parameters used for calibration of the measuring device 10 itself based on the position change of the element to be measured 31 based on the movement of the calibration fixture 30. Here, since the calibration fixture 30 is provided with a plurality of elements to be measured 31, it is desirable that the measuring device 10 can identify each element to be measured 31.

[0220] In particular, it is desirable that the measuring device 10 can identify each of the components to be measured 31 from the photographing results obtained by photographing the plurality of components to be measured 31. For example, as described above, the plurality of components to be measured 31 may have different shapes, marks, colors, etc. However, since the plurality of imaging units 132 photograph the calibration jig 30 from different angles, there is a case where it is difficult to identify each of the components to be measured 31 from the respective photographing results. Therefore, the following will describe a calibration jig 300 that enables the measuring device 10 to easily identify the components to be measured 31.

[0221] <First Configuration Example of the Calibration Jig 300>

[0222] Figure 8 A first configuration example of the calibration jig 300 according to the present embodiment is shown. Figure 8 In the calibration fixture 300 shown, Figure 2 The operations of the calibration jig 30 according to the present embodiment shown in the drawings are approximately the same as those of the calibration jig 300, and redundant description thereof is omitted. Figure 2 The calibration jig 300 is shown. The calibration jig 300 may be formed as a reference jig for calibrating each optical unit 130. The calibration jig 300 includes a plurality of elements to be measured 31 and a frame portion 40.

[0223] A plurality of elements to be measured 31 are attached to the frame portion 40. Figure 8An example in which the frame portion 40 is a plate member is shown, but it is not limited thereto. The frame portion 40 may be any member as long as it can fix the element to be measured 31, and may be a rod-shaped member or the like.

[0224] and Figure 2 similar, Figure 8 An example is shown in which the first element to be measured 31a is in the field of view 133a of the first imaging section 132a of the first optical unit 130a and the second element to be measured 31b is in the field of view 133b of the second imaging section 132b of the second optical unit 130b. Figure 8 The number of components 31 to be measured is less than Figure 2 , but more elements to be measured 31 can be attached to the frame portion 40.

[0225] <First Configuration Example of Element to be Measured 31>

[0226] Fig. 9 (A) and (B) of FIG. 1 each show a first configuration example of the element to be measured 31 according to the present embodiment. Fig. 9 As shown in (A), the element to be measured 31 includes a main body 32, a label part 33 and a plate member 34. The main body 32 has a predetermined shape. The shape of the main body 32 is, for example, a rotating body such as a sphere, an ellipsoid or a cylinder. Alternatively, the shape of the main body 32 may be a polyhedron.

[0227] Fig. 9 (A) and (B) each show an example in which a plurality of label portions 33 are attached to a plate member 34 by a known method such as printing or pasting, and the label portions 33 are provided on the main body portion 32 via the plate member 34. It is desirable that the label portions 33 are provided on many parts of the main body portion 32. For example, the main body portion 32 has a plurality of plate members 34, and a plurality of label portions 33 are provided at a plurality of different positions on the main body portion 32, so that when the element to be measured 31 is photographed from various angles, at least one label portion 33 is included in the photographed image.

[0228] The plate member 34 is a belt-shaped member provided around the main body portion 32. A plurality of label portions 33 may be provided on the plate member 34. It is desirable that a plurality of label portions 33 are provided on both the front and back surfaces of the plate member 34. Fig. 9 (A) and (B) each show an example in which four label portions 33 are provided on one side of the plate member 34. As described above, the label portion 33 may be provided on the plate member 34, or may be provided on other parts of the main body portion 32 instead of or in addition to the plate member 34.

[0229] Fig. 9(B) shows an example in which a single label portion 33 is shown as a rectangular shape, wherein the single label portion 33 is shown as Fig. 9 L1 to L2 of the plate member 34 shown in (A). The label portion 33 includes, for example, an identification code 35 and an identification code 36.

[0230] The identification code 35 is a code for identifying the label portion 33, which is common to the plurality of components to be measured 31. The identification code 36 is a code for identifying the component to be measured 31. It is desirable that the identification code 35 and the identification code 36 are codes of different shapes or codes of different types. For example, the identification code 36 is composed of a combination of basic components of a predetermined first shape, while the identification code 35 is composed of a combination of basic components of a predetermined second shape having a size different from that of the first shape.

[0231] Fig. 9 (A) and (B) of FIG. 3 each show an example in which the identification code 35 and the identification code 36 are indicated in bar codes having different line widths. As an example, the minimum line width d of the identification code 35 is half the minimum line width D of the identification code 36. The identification code 35 and the identification code 36 each indicate a predetermined value. As an example, the identification code 35 indicates a predetermined 8-bit value (01010101), and the identification code 36 indicates a predetermined 8-bit value (01001010).

[0232] Fig.10 Show that it can be based on Fig. 9 The example of the brightness signal obtained by the tag part 33 shown in (A) and (B) of FIG. The brightness signal of the photographing result obtained by photographing the tag part 33 by using the camera 132 corresponds to the identification code 35 and the identification code 36. For example, the control unit 240 can detect the tag part 33 by pattern matching (i) a predetermined signal pattern corresponding to the identification code 35 and (ii) the brightness signal.

[0233] For example, the predetermined signal pattern is preset by the pattern signal width W, the unit pattern width D, the brightness signal level H, and the binarization reference level I0, etc. The desired predetermined signal pattern is stored in the storage unit 220. When the predetermined signal pattern and the brightness signal match, the control unit 240 reads a predetermined number (e.g., eight) of brightness signals after the matching brightness signal, and the width of each brightness signal is the width D. The brightness signal with the width D may correspond to one bit. For example, the control unit 240 identifies the value of each bit of the identification code 36 by comparing the read signal level with the binarization reference level I0.

[0234] As described above, the control unit 240 can read the identification code 36 by detecting the identification code 35 from the captured image. Here, since the minimum line width d of the identification code 35 is different from the minimum line width D of the identification code 36, it is possible to reduce erroneous detection of a part of the identification code 36 as a part of the identification code 35. In addition, by setting the minimum line width D of the identification code 36 to be larger than the minimum line width d of the identification code 35, the accuracy of reading the identification code 36 can be improved.

[0235] Since the camera unit 132 takes pictures of the component to be measured 31 from various angles, Fig. 9 As shown in (A), there may be a case where the tag portion 33 cannot be photographed from the front angle. Therefore, the control unit 240 can perform image processing on the photographing results of the camera unit 132 to convert them into other image data suitable for detecting the tag portion 33.

[0236] Fig.11 (A) to (C) show examples of steps involved in image processing performed by the control section 240 on the image pickup result of the image pickup section 132 according to the present embodiment. Fig.11 (A) shows an example of a result of imaging by the imaging unit 132 . Fig.11 The photographing result shown in (A) shows an example in which the label portion 33 is photographed from a certain angle. Fig.11 (B) shows an example of an ideal photographing result of the imaging unit 132. The ideal photographing result shows an example of photographing the label unit 33 from a straight forward angle. It is desirable to store such an ideal photographing result in the storage unit 220 as image data.

[0237] For example, the control unit 240 Fig.11 The control unit 240 calculates the image data ID of the component to be measured 31 from the image capturing result of the image capturing unit 132 shown in (A). Fig.11 The ideal image data IID image of the element to be measured 31 shown in (B) is transformed into Fig.11 The control unit 240 calculates the transformation matrix TI of the extracted image data ID of the element to be measured 31 shown in (A). For example, the control unit 240 calculates the transformation matrix TI so that the calculation result of IID×TI becomes the image data ID.

[0238] Then, the control unit 240 calculates the inverse matrix TI of the transformation matrix TI -1 , and by multiplying the image data ID of the element to be measured 31 by the calculated inverse matrix TI -1 To transform the image. Fig.11(C) shows an example of the result of image transformation of the shooting result of the camera unit 132. Through the above-mentioned image transformation, the control unit 240 can transform the label unit 33 photographed from a certain angle in the shooting result of the camera unit 132 into an image viewed from the front angle. The control unit 240 can also perform image processing on the image of the label unit 33 to transform the label unit 33 into an image viewed from the front angle. Fig. 9 In this case, the control unit 240 performs image processing such as polar coordinate conversion.

[0239] As described above, the control section 240 can easily read the identification code 36 of the label section 33 from the photographing result of the imaging section 132. Therefore, the control section 240 can identify each of the plurality of components to be measured 31 included in the photographed image according to the identification code 36. In this way, the control section 240 can reduce misidentification of the components to be measured 31, for example, before and after the movement of the calibration jig 300. Therefore, according to the calibration jig 300 of the present embodiment, the measuring device 10 can be easily calibrated.

[0240] An example in which the identification code 35 and the identification code 36 are bar codes in the element to be measured 31 according to the present embodiment is described, but the present disclosure is not limited thereto. The identification code 35 and the identification code 36 may be QR codes (registered trademark), predetermined symbols, predetermined graphics, etc. In addition, the identification code 35 may include a basic component of a predetermined color different from the color of the basic component of the first shape constituting the identification code 36.

[0241] <Second Configuration Example of Element to be Measured 31>

[0242] Fig.12 (A) and (B) of FIG. 1 each show a second configuration example of the element to be measured 31 according to the present embodiment. In the element to be measured 31 of the second configuration example, Fig. 9 The operations of the element to be measured 31 of the first configuration example shown in (A) and (B) are denoted by the same reference numerals, and redundant description thereof is omitted. In the element to be measured 31 of the second configuration example, the identification code 35 is composed of a basic component of a predetermined color.

[0243] The predetermined color is different from the color of the basic components constituting the identification code 36. The predetermined color may be any color that the camera unit 132 can handle as a captured image. For example, in the case where the camera unit 132 can output a color captured image, the predetermined color may be red, green, or blue, or may be a color obtained by mixing these colors. In the case where the camera unit 132 can output a black-and-white captured image, the predetermined color may be a grayscale color. The minimum line width d of the identification code 35 may be the same as or different from the minimum line width D of the identification code 36.

[0244] Fig.13 Show that it can be based on Fig.12 The brightness signal obtained by the tag part 33 shown in (A) and (B) of FIG. 1 corresponds to the identification code 35 and the recognition code 36. Fig.10 As described above, the control unit 240 may detect the tag unit 33 by pattern matching a predetermined signal pattern corresponding to the identification code 35 and the brightness signal.

[0245] For example, according to the mode signal width D, brightness signal level I S As well as the binary reference level I0, the predetermined signal mode is preset. Since the brightness signal of the identification code 35 has a signal level corresponding to the predetermined color, the predetermined signal mode can be compared to Fig.10 The predetermined signal pattern shown is simple.

[0246] When the predetermined signal pattern and the brightness signal match, the control unit 240 reads the brightness signal of a predetermined number of bits (e.g., eight) after the matching brightness signal, and the width of each brightness signal is the width D. It is desirable that the control unit 240 performs pattern matching between (i) the brightness signal of the two identification codes 35 sandwiching the identification code 36 and (ii) the predetermined signal pattern. In this way, the control unit 240 can identify the identification code 36 while reducing the false detection of the identification code 35.

[0247] <Third Configuration Example of Element to be Measured 31>

[0248] Fig.14 (A) and (B) of FIG. 1 each show a third configuration example of the element to be measured 31 according to the present embodiment. In the element to be measured 31 of the third configuration example, Fig. 9 The operations of the element to be measured 31 of the first configuration example shown in (A) and (B) are denoted by the same reference numerals, and redundant descriptions thereof are omitted. The element to be measured 31 of the third configuration example includes an identification code 35 including a portion showing a predetermined image.

[0249] The predetermined image may be any image as long as it is different from the combination of the basic components constituting the identification code 36. The color of the predetermined image may be the same as or different from the color of the basic components constituting the identification code 36. The width of the portion of the identification code 35 may be the same as or different from the minimum line width D of the identification code 36.

[0250] The control section 240 can detect the label section 33 by performing pattern matching in the captured image of the component to be measured 31 using a search pattern corresponding to a predetermined image of the identification code 35. It is desirable that the control section 240 performs pattern matching between (i) the images of the two identification codes 35 sandwiching the identification code 36 and (ii) the predetermined search pattern. When the predetermined search pattern and the image of the identification code 35 match, the control section 240 can identify the identification code 36 by reading a brightness signal of an image after the matched identification code 35.

[0251] <Fourth Configuration Example of Element to be Measured 31>

[0252] Fig.15 A fourth configuration example of the element to be measured 31 according to the present embodiment is shown. In the element to be measured 31 of the fourth configuration example, Fig. 9 The operations of the element to be measured 31 of the first configuration example shown in (A) and (B) are approximately the same as the operations denoted by the same reference numerals, and their redundant descriptions are omitted. Similar to the element to be measured 31 of the third configuration example, the element to be measured 31 of the fourth configuration example includes an identification code 35 including a portion showing a predetermined image.

[0253] The predetermined image includes a pattern of a predetermined shape or a pattern of a combination of predetermined shapes, or the like. Fig.15 An example is shown in which the predetermined image includes a pattern having a circular shape. Alternatively, the predetermined image may include patterns such as a polygon, a heart, and a spade, etc. Since such a shape is not accidentally formed in the captured image of the calibration fixture 300, the control section 240 can improve the accuracy of pattern matching the image of the identification code 35 and the predetermined search pattern.

[0254] As described above, the control section 240 can read the identification code 36 from the captured image based on the identification code 35 by using any one of the components to be measured 31 of the second to fourth configuration examples. Furthermore, needless to say, even in the case of using any one of the components to be measured 31 of the second to fourth configuration examples, it is possible to perform Fig.11 The label portion 33 can be easily read by the image processing described in (A) to (C) of FIG. Therefore, the calibration jig 300 using any one of the components to be measured 31 of the second to fourth configuration examples can also easily perform calibration of the measuring device 10 .

[0255] In the calibration jig 300 according to the present embodiment described above, an example is described in which the element to be measured 31 includes the plate member 34 provided with the label portion 33, but the present disclosure is not limited thereto. The label portion 33 may be provided on the body portion 32 of the element to be measured 31. It should be noted that when a plurality of label portions 33 are provided on the body portion 32, the plate member 34 does not need to be provided.

[0256] In addition, in the calibration jig 300 according to the present embodiment, an example in which the frame portion 40 is a plate member is described, but the present disclosure is not limited thereto. For example, the frame portion 40 may have a spherical or elliptical shape.

[0257] <Second Configuration Example of Calibration Jig 300>

[0258] Fig.16 A second configuration example of the calibration jig 300 according to the present embodiment is shown. In the calibration jig 300 of the second configuration example, the frame portion 40 has a spherical or elliptical shape. The frame portion 40 may be formed into a spherical or elliptical shape at least in part by combining a plurality of rod-shaped members, etc. In addition, the frame portion 40 may include a member having the shape of at least a portion of a sphere or an ellipsoid.

[0259] The frame portion 40 includes, for example, a plurality of rod-shaped members 41 also in an arc shape, a columnar member 42, and a base 43. The plurality of rod-shaped members 41 can be attached to the columnar member 42 so as to be rotatable around the columnar member 42 as an axis. The columnar member 42 is attached to the base 43. It is desirable that the surfaces of the plurality of rod-shaped members 41 in contact with the outside form a spherical surface or an ellipsoid.

[0260] The arc-shaped rod-shaped members 41 are each provided to be movable in the Z direction. The arc-shaped rod-shaped members 41 can each be configured to be movable in the circumferential direction of a circle described by the arc. A plurality of elements to be measured 31 are fixed to the outside of the plurality of rod-shaped members 41. In this way, the plurality of elements to be measured 31 can be configured in a spherical configuration or an elliptical configuration. Fig.16 An example of the spherical frame portion 40 in which the columnar member 42 extends in the Z direction and the plurality of rod-shaped members 41 are provided to be rotatable around the Z direction as an axis is shown.

[0261] The configuration position and / or orientation of the plurality of imaging units 132 may be changed according to the measurement object. By configuring the plurality of elements 31 to be measured in such a spherical configuration, the plurality of elements 31 to be measured may be included in each field of view of the imaging unit 132 even when the configuration position and / or orientation of the imaging unit 132 is changed. The imaging unit 132 may be arranged to surround the measurement object. In this case, the configuration position and orientation may be different for each imaging unit 132. Even in this case, by configuring the plurality of elements 31 to be measured in a spherical configuration, the plurality of elements 31 to be measured may be included in each field of view of the imaging unit 132.

[0262] The plurality of elements to be measured 31 are each disposed on a spherical or ellipsoidal surface of the frame portion 40. The plurality of elements to be measured 31 are disposed, for example, so that adjacent elements to be measured 31 are within a predetermined distance range on the spherical surface of the sphere formed by the frame portion 40. Here, for example, when the main body portion 32 of the element to be measured 31 is a sphere, the predetermined distance is approximately two to four times the diameter of the sphere. When the main body portion 32 of the element to be measured 31 is an ellipsoid, the predetermined distance may be approximately two to four times the major axis of the ellipsoid.

[0263] It is desirable that the elements to be measured 31 are arranged so that the label portion 33 is included in the field of view of more camera units 132. An example is envisioned in which the frame portion 40 is regarded as a spherical body with the Z direction as the rotation axis and has spherical coordinates similar to the spherical coordinates of a celestial body or the like. It is desirable that a plurality of elements to be measured 31 are arranged in the same latitude direction and / or the same longitude direction of such a spherical body. In addition, each of the elements to be measured 31 is arranged, for example, so that at least one label portion 33 is shown in a plane that is orthogonal to the normal direction of the spherical body and faces the outside of the frame portion 40.

[0264] For example, it is desirable to densely arrange the plurality of elements to be measured 31 on the spherical surface of the sphere so that even when the imaging unit 132 captures a portion of the calibration jig 300, the plurality of elements to be measured 31 whose label portions 33 can be read are included in the captured image. In this way, the plurality of elements to be measured 31 can be identified in the captured images of the calibration jig 300 captured by the plurality of imaging units 132 simply by mounting only one calibration jig 300 of the second configuration example on the stage 110.

[0265] Therefore, as described above, the calibration parameters to be used for calibration of the plurality of imaging units 132 themselves can be identified based on the captured images of the calibration jig 300 obtained by the plurality of imaging units 132 before and after the movement of the calibration jig 300. An example in which the calibration jig 300 is mounted on the stage 110 and moves when identifying the above-mentioned calibration parameters is described, but the present disclosure is not limited thereto. In addition to the movement of the stage 110, the calibration jig 300 may be configured so that the plurality of elements to be measured 31 can be moved while maintaining their relative positional relationship.

[0266] The calibration fixture 300, for example, also includes a frame moving portion for moving the frame portion 40 together with the plurality of elements to be measured 31. The frame moving portion includes an actuator such as a motor, etc., and moves the frame portion 40 in a plurality of predetermined directions. In addition, the frame moving portion can rotate the frame portion 40 around an axis oriented in a predetermined direction. The frame moving portion is, for example, configured so that it can move the plurality of elements to be measured 31 in the X direction, the Y direction, and the Z direction. In addition, the frame moving portion can be configured so that it can rotate the plurality of elements to be measured 31 around the X direction, the Y direction, and the Z direction as rotation axes. In this way, the measuring device 10 can identify the calibration parameters to be used for calibration by moving the frame portion 40 of the calibration fixture 300 without moving the stage 110.

[0267] For example, in Figure 4 In S54 of the illustrated operation flow, the control unit 240 photographs the calibration jig 300 arranged at the first reference position. The first imaging unit 132a photographs the calibration jig 300 so that some first elements 31a to be measured among the plurality of elements 31 to be measured disposed in the calibration jig 300 are included in the field of view of the first imaging unit 132a. The second imaging unit 132b different from the first imaging unit 132a photographs the calibration jig 300 so that some second elements 31b to be measured different from the first elements 31a to be measured photographed by the first imaging unit 132a are included in the field of view of the second imaging unit 132b.

[0268] The photographing of the calibration jig 300 in S58, S59, S61 and S63 is the same as the photographing in S54. In addition, in S55, S57, S60 and S62, the control unit 240 may move the stage 110, or alternatively, may move the calibration jig 300 by controlling the frame moving unit of the calibration jig 300.

[0269] Then, in S64, the measuring unit 243 analyzes the label portion 33 of the component to be measured 31 from the captured image captured by the first imaging unit 132a to identify the first component to be measured 31a. The measuring unit 243 identifies a first coordinate position indicating the position of the identified first component to be measured 31a in the first coordinate system based on the field of view of the first imaging unit 132a.

[0270] Similarly, the measuring unit 243 analyzes the label portion 33 of the component to be measured from the captured image captured by the second imaging unit 132b to identify the second component to be measured 31b. The measuring unit 243 identifies a second coordinate position indicating the position of the identified second component to be measured 31b in the second coordinate system based on the field of view of the second imaging unit 132b.

[0271] After S64 , as described above, calibration parameters for calibrating the first imaging unit 132 a and the second imaging unit 132 b may be identified based on the positional relationship between the identified first component to be measured 31 a and the identified second component to be measured 31 b .

[0272] In addition, Figure 4 In S51 and S52 of the illustrated operation flow, an example is described of calibrating each optical unit 130 using a reference jig smaller in size than the calibration jig 30. Here, since the calibration jig 300 of the second configuration example can be made smaller in size than the calibration jig 30, the calibration jig 300 can also be used as a reference jig.

[0273] For example, by storing in advance in the storage unit 220 or the like at least the measured dimensions and positional relationships of a subset of the plurality of elements 31 to be measured, the calibration jig 300 can be used as a reference jig. In other words, the measuring device 10 can perform the measurement using one calibration jig 300. Figure 4 The operation flow shown.

[0274] The present invention has been described based on exemplary embodiments. The technical scope of the present invention is not limited to the scope described in the above embodiments, and various changes and modifications can be made within the scope of the present invention. For example, all or part of the device can be configured with any unit that is functionally or physically distributed or integrated. In addition, new exemplary embodiments generated by any combination of exemplary embodiments are included in the exemplary embodiments of the present invention. In addition, the effects of the new embodiments brought about by the combination also have the effects of the original exemplary embodiments together.

Claims

1. A calibration fixture for calibrating a measuring device, wherein the measuring device is used to measure the three-dimensional geometric shape of a measuring object and comprises a plurality of camera units for photographing the measuring object, the calibration fixture comprising: Multiple components to be measured; as well as a frame portion to which the plurality of elements to be measured are attached, Wherein, each of the plurality of elements to be measured comprises: a main body portion having a predetermined shape; and A plurality of label parts are arranged on the main body, wherein an identification code for identifying the element to be measured is shown on each label part.

2. The calibration fixture according to claim 1, wherein: The label portion further includes an identification code common to the plurality of components to be measured and used to identify the label portion.

3. The calibration fixture according to claim 2, wherein: The identification code is composed of a combination of basic components of a predetermined first shape, and The identification code is composed of a combination of basic components of a predetermined second shape having a size different from that of the first shape.

4. The calibration fixture according to claim 2, wherein: The identification code is composed of a combination of basic components of a predetermined first shape, and The identification code includes a basic component of a predetermined color different from the color of the basic component of the first shape.

5. The calibration fixture according to claim 2, wherein: The identification code is composed of a combination of basic components of a predetermined first shape, and The identification code includes a portion showing a predetermined image.

6. The calibration fixture according to claim 2, wherein: The identification code and the identification code are formed by a bar code, and The minimum line width of the barcode of the identification code is different from the minimum line width of the barcode of the recognition code.

7. The calibration fixture according to claim 6, wherein: The minimum line width of the barcode of the identification code is greater than the minimum line width of the barcode of the recognition code.

8. The calibration fixture according to claim 1, wherein: Each of the plurality of elements to be measured further comprises: a strip-shaped plate member disposed around the main body portion, and The plurality of label portions are provided on the plate member.

9. The calibration fixture of claim 1, further comprising: The frame moving part is used to move the frame part and the plurality of components to be measured together.

10. The calibration fixture according to any one of claims 1 to 9, wherein: The frame portion has a spherical or elliptical shape, and The plurality of elements to be measured are each disposed on a spherical or elliptical surface of the frame portion.

11. A calibration method for calibrating a measuring device using a calibration fixture, the measuring device being used to measure a three-dimensional geometric shape of a measuring object and comprising a plurality of camera units for photographing the measuring object, wherein: The calibration fixture includes a plurality of components to be measured, Each of the plurality of elements to be measured comprises: a main body portion having a predetermined shape; and a plurality of label parts, which are arranged on the main body, wherein an identification code for identifying the element to be measured is shown on each label part, and The calibration method comprises: a first imaging step for photographing the calibration jig using the first imaging unit in such a manner that a portion of first elements to be measured among the plurality of elements to be measured are included in a field of view of the first imaging unit, and photographing the calibration jig using the second imaging unit in such a manner that a portion of second elements to be measured different from the first elements to be measured photographed by the first imaging unit are included in a field of view of a second imaging unit different from the first imaging unit; The step of identifying the component to be measured comprises: identifying the first component to be measured by analyzing the label portion of the component to be measured from the image captured by the first imaging unit, and identifying the second component to be measured by analyzing the label portion of the component to be measured from the image captured by the second imaging unit; and A step for identifying calibration parameters for calibrating the first imaging unit and the second imaging unit according to a positional relationship between the identified first component to be measured and the identified second component to be measured.

12. The calibration method according to claim 11, wherein: The steps for identifying the component to be measured include: extracting the image data ID of the first component to be measured from the image captured by the first camera unit; Using the ideal image data IID of the first element to be measured to calculate the transformation matrix TI, so that the calculation result of IID×TI becomes the image data ID of the first element to be measured; Calculate the inverse matrix TI of the transformation matrix TI -1 ; By multiplying the image data ID of the first element to be measured by the calculated inverse matrix TI -1 to perform image transformation; and The identification code of the label portion provided in the first component to be measured is read from the data obtained by converting the image data ID.

13. The calibration method according to claim 11 or 12, further comprising: a second imaging step, for photographing the first component to be measured by using the first imaging unit and photographing the second component to be measured by using the second imaging unit after the calibration fixture is moved in a predetermined first direction after the first imaging step; a third imaging step for, after the second imaging step, photographing the first component to be measured by using the first imaging unit and photographing the second component to be measured by using the second imaging unit after the calibration fixture is moved in a predetermined second direction different from the first direction; A fourth imaging step, for photographing the first component to be measured by using the first imaging unit and photographing the second component to be measured by using the second imaging unit; a fifth imaging step for, after the fourth imaging step, photographing the first component to be measured by using the first imaging unit and photographing the second component to be measured by using the second imaging unit after rotating the calibration fixture around an axis oriented in a predetermined third direction; a sixth imaging step for, after the fifth imaging step, photographing the first component to be measured using the first imaging unit and photographing the second component to be measured using the second imaging unit after rotating the calibration fixture around an axis oriented in a predetermined fourth direction different from the third direction; as well as a step of identifying a first coordinate position in a plurality of images captured by the first camera unit and identifying a second coordinate position in a plurality of images captured by the second camera unit, wherein the first coordinate position is used to indicate a position of the first element to be measured in a first coordinate system based on the field of view of the first camera unit, and the second coordinate position is used to indicate a position of the second element to be measured in a second coordinate system based on the field of view of the second camera unit, The step of identifying the calibration parameters comprises: Identifying a first rotation matrix for rotating the first coordinate system and a second rotation matrix for rotating the second coordinate system to perform coordinate transformation so that the direction in which the first coordinate position moves and the direction in which the second coordinate position moves are consistent with each other before and after the calibration fixture moves in the first direction and the second direction; and A first translation vector for translating the first coordinate system and a second translation vector for translating the second coordinate system are identified so that the distance between the first component to be measured and the second component to be measured is equal before and after rotating the calibration fixture.

14. The calibration method according to claim 13, further comprising: After identifying the first rotation matrix, the second rotation matrix, the first translation vector and the second translation vector, the first coordinate position and the second coordinate position are transformed into a calibration coordinate system by (i) rotating the first coordinate position using the first rotation matrix and translating the rotated first coordinate position using the first translation vector and (ii) rotating the second coordinate position using the second rotation matrix and translating the rotated second coordinate position using the second translation vector.

15. A measurement system comprising: Measuring equipment for measuring the three-dimensional geometric shape of the measurement object; as well as a calibration fixture for calibrating the measuring device, Wherein, the measuring device comprises: a moving part, on which the measurement object is mounted and which moves the measurement object; a light source, for irradiating light onto the measurement object; A plurality of camera units, used for respectively photographing a plurality of different areas of the measurement object; A measuring unit, configured to measure the three-dimensional geometric shape of the measurement object based on the photographing results of the multiple camera units; a control unit, configured to control the moving unit, the imaging unit, and the measuring unit; and an identification unit for identifying a calibration parameter for calibrating the measurement result of the measurement unit, and The calibration fixture comprises: a plurality of components to be measured; and a frame portion to which the plurality of elements to be measured are attached, Wherein, each of the plurality of elements to be measured comprises: a main body portion having a predetermined shape; and a plurality of label parts, which are arranged on the main body, wherein an identification code for identifying the element to be measured is shown on each label part, The control unit causes the plurality of imaging units to capture images of subsets of the plurality of elements to be measured, the subsets being different from each other. The measuring section analyzes the label portions of the plurality of components to be measured corresponding to the respective images of the plurality of images captured by the plurality of imaging sections to identify the positional relationship between the plurality of components to be measured, and The recognition unit recognizes calibration parameters for calibrating the plurality of imaging units according to the recognized positional relationship of the plurality of components to be measured.

Images